Uplink control information transmission method and apparatus

ABSTRACT

A terminal receives downlink scheduling information of a downlink subframe F(i, j), where a set M of preconfigured downlink subframes in which the downlink subframe F(i, j) is located is divided into N subsets of preconfigured downlink subframes, a bit quantity of a hybrid automatic repeat request-acknowledgement HARQ-ACK that needs to be fed back for each downlink subframe in one subset of preconfigured downlink subframes is a predetermined value, and bit quantities of HARQ-ACKs that need to be fed back for any downlink subframes in different subsets of preconfigured downlink subframes are different. The terminal generates a HARQ-ACK codebook according to a receiving status of downlink data. And the terminal generates uplink control information after encoding the HARQ-ACK codebook; and a sending module sends the uplink control information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2015/086692, filed on Aug. 11, 2015, which claims priority toInternational Application No. PCT/CN2015/086538, filed on Aug. 10, 2015.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the field of wireless communicationstechnologies, and in particular, to a terminal, an access networkdevice, a wireless communications system, and an uplink controlinformation transmission method.

BACKGROUND

In a Long Term Evolution (LTE) system, a hybrid automatic repeat request(HARQ) mechanism is used for downlink data transmission. After userequipment (UE) receives a physical downlink shared channel (PDSCH), ifthe physical downlink shared channel is correctly received, the UE feedsback an acknowledgment (ACK) on a physical uplink control channel(PUCCH), and if the physical downlink shared channel is incorrectlyreceived, the UE feeds back a negative acknowledgement (NACK) on thePUCCH. The ACK and the NACK are collectively referred to as a HARQ-ACK.

The LTE system supports a carrier aggregation (CA) technology, that is,an access network device configures a plurality of carriers for one UE,to improve a data rate of the UE. As shown in FIG. 1, a base stationtransmits downlink data to UE 1 by using a carrier 1 and a carrier 2,and the base station transmits downlink data to UE 2 by using a carrier1, a carrier 3, and a carrier 5.

As shown in Table 1, there are a plurality of data channel transmissionmodes in a current LTE system.

TABLE 1 Data channel PDSCH transmission mode in an LTE system Mode 1Cell-specific reference signal Single-antenna port Mode 2 (CRS) based onantenna Transmit diversity Mode 3 ports 0 to 3 Open-loop space divisionmultiplex Mode 4 Closed-loop space division multiplex Mode 5 Multi-usermultiplex Mode 6 Single-layer closed-loop space division multiplex Mode7 Demodulation reference signal Single-antenna port (DMRS) based on anantenna port 5 Mode 8 DMRS based on antenna ports Double current 7 and 8transmission Mode 9 DMRS based on antenna ports One to eight layers of 7to 14 transmission

A PDSCH scheduled in a downlink subframe in the transmission modes 1, 2,5, 6, and 7 is a single transport block, that is, each downlink subframecorresponds to one HARQ-ACK bit, and a PDSCH scheduled in a downlinksubframe in the transmission modes 3, 4, 8, and 9 may be two transportblocks, that is, each downlink subframe corresponds to two HARQ-ACKbits.

Currently, in a CA mode, to-be-aggregated carriers usually have a samePDSCH transmission mode. Therefore, bit quantities of HARQ-ACKs thatneed to be fed back by the UE for downlink subframes on theto-be-aggregated carriers are the same. However, as technologiesdevelop, to-be-aggregated carriers may have different PDSCH transmissionmodes. For example, aggregation of a maximum of five carriers issupported currently, and aggregation of 10 carriers, 20 carriers, oreven 32 carriers may appear later. In this case, to-be-aggregatedcarriers may have different PDSCH transmission modes, and bit quantitiesof HARQ-ACKs that need to be fed back for downlink subframes ondifferent carriers are different. Currently, the UE does not supportsuch a case in which bit quantities of HARQ-ACKs that need to be fedback for downlink subframes on different to-be-aggregated carriers aredifferent.

SUMMARY

In view of this, embodiments of the present disclosure provide aterminal, an access network device, a wireless communications system,and an uplink control information transmission method, to support a casein which bit quantities of HARQ-ACKs that need to be fed back fordownlink subframes on different to-be-aggregated carriers are different.

According to a first aspect, an embodiment of the present disclosureprovides a terminal, including:

-   -   a receiving module, configured to receive downlink scheduling        information of a downlink subframe F(i, j), where the downlink        subframe F(i, j) is a subframe in a set M of preconfigured        downlink subframes corresponding to an uplink subframe; where    -   F(i, j) represents a downlink subframe j on a carrier i        configured for the terminal, iϵC, C is a set of all carriers        configured for the terminal for downlink data transmission, jϵK,        and K is a set of downlink subframes corresponding to the uplink        subframe;    -   the set M of preconfigured downlink subframes is divided into N        subsets of preconfigured downlink subframes, N is an integer        greater than or equal to 2, a bit quantity of a hybrid automatic        repeat request-acknowledgement HARQ-ACK that needs to be fed        back for each downlink subframe in one subset of preconfigured        downlink subframes is a predetermined value, and bit quantities        of HARQ-ACKs that need to be fed back for any downlink subframes        in different subsets of preconfigured downlink subframes are        different; and    -   the receiving module is further configured to receive, in the        downlink subframe F(i, j), downlink data scheduled by the        downlink scheduling information;    -   a processing module, configured to: generate a HARQ-ACK codebook        according to a receiving status of the downlink data received by        the receiving module in the downlink subframe F(i, j) and a bit        quantity of a HARQ-ACK that needs to be fed back for the        downlink subframe F(i, j), where the HARQ-ACK codebook includes        at least one sub-codebook, the at least one sub-codebook is in        one-to-one correspondence with at least one subset of        preconfigured downlink subframes, the at least one subset of        preconfigured downlink subframes is at least one of the N        subsets of preconfigured downlink subframes, and the at least        one subset of preconfigured downlink subframes is a subset        including the downlink subframe in which the terminal receives        the downlink data scheduled by the downlink scheduling        information; and generate uplink control information by encoding        the HARQ-ACK codebook; and    -   a sending module, configured to send the uplink control        information in the uplink subframe.

According to a second aspect, an embodiment of the present disclosureprovides an access network device, including:

-   -   a sending module, configured to: send downlink scheduling        information of a downlink subframe F(i, j) to a terminal, and        send, to the terminal in the downlink subframe F(i, j), downlink        data scheduled by the downlink scheduling information, where the        downlink subframe F(i, j) is a subframe in a set M of        preconfigured downlink subframes corresponding to an uplink        subframe; where    -   F(i, j) represents a downlink subframe j on a carrier i        configured for the terminal, iϵC, C is a set of all carriers        configured for the terminal for downlink data transmission, jϵK,        and K is a set of downlink subframes corresponding to the uplink        subframe; and    -   the set M of preconfigured downlink subframes is divided into N        subsets of preconfigured downlink subframes, N is an integer        greater than or equal to 2, a bit quantity of a HARQ-ACK that        needs to be fed back for each downlink subframe in one subset of        preconfigured downlink subframes is a predetermined value, and        bit quantities of hybrid automatic repeat        request-acknowledgements HARQ-ACKs that need to be fed back for        any downlink subframes in different subsets of preconfigured        downlink subframes are different;    -   a receiving module, configured to receive uplink control        information that is sent by the terminal in the uplink subframe        and that is used for feeding back a receiving status of the        downlink data scheduled by the downlink scheduling information;        and    -   a processing module, configured to obtain a HARQ-ACK codebook by        decoding the uplink control information, where the obtained        HARQ-ACK codebook includes at least one sub-codebook, the at        least one sub-codebook is in one-to-one correspondence with at        least one subset of preconfigured downlink subframes, the at        least one subset of preconfigured downlink subframes is at least        one of the N subsets of preconfigured downlink subframes, and        the at least one subset of preconfigured downlink subframes is a        subset including downlink subframes in which the downlink data        scheduled by the downlink scheduling information is sent.

According to a third aspect, an embodiment of the present disclosureprovides an uplink control information sending method, including:

-   -   receiving, by a terminal, downlink scheduling information of a        downlink subframe F(i, j), where the downlink subframe F(i, j)        is a subframe in a set M of preconfigured downlink subframes        corresponding to an uplink subframe; where    -   F(i, j) represents a downlink subframe j on a carrier i        configured for the terminal, iϵ, C is a set of all carriers        configured for the terminal for downlink data transmission, jϵK,        and K is a set of downlink subframes corresponding to the uplink        subframe; and    -   the set M of preconfigured downlink subframes is divided into N        subsets of preconfigured downlink subframes, N is an integer        greater than or equal to 2, a bit quantity of a hybrid automatic        repeat request-acknowledgement HARQ-ACK that needs to be fed        back for each downlink subframe in one subset of preconfigured        downlink subframes is a predetermined value, and bit quantities        of HARQ-ACKs that need to be fed back for any downlink subframes        in different subsets of preconfigured downlink subframes are        different;    -   receiving, by the terminal in the downlink subframe F(i, j),        downlink data scheduled by the downlink scheduling information;    -   generating, by the terminal, a HARQ-ACK codebook according to a        receiving status of the downlink data received in the downlink        subframe F(i, j) and a bit quantity of a HARQ-ACK that needs to        be fed back for the downlink subframe F(i, j), where the        HARQ-ACK codebook includes at least one sub-codebook, the at        least one sub-codebook is in one-to-one correspondence with at        least one subset of preconfigured downlink subframes, the at        least one subset of preconfigured downlink subframes is at least        one of the N subsets of preconfigured downlink subframes, and        the at least one subset of preconfigured downlink subframes is a        subset including the downlink subframe in which the terminal        receives the downlink data scheduled by the downlink scheduling        information;    -   generating uplink control information by encoding the HARQ-ACK        codebook; and    -   sending, by the terminal, the uplink control information in the        uplink subframe.

According to a fourth aspect, an embodiment of the present disclosureprovides an uplink control information receiving method, including:

-   -   sending, by an access network device, downlink scheduling        information of a downlink subframe F(i, j) to a terminal, and        sending, to the terminal in the downlink subframe F(i, j),        downlink data scheduled by the downlink scheduling information,        where the downlink subframe F(i, j) is a subframe in a set M of        preconfigured downlink subframes corresponding to an uplink        subframe; where    -   F(i, j) represents a downlink subframe j on a carrier i        configured for the terminal, iϵC, C is a set of all carriers        configured for the terminal for downlink data transmission,    -   jϵK, and K is a set of downlink subframes corresponding to the        uplink subframe; and the set M of preconfigured downlink        subframes is divided into N subsets of preconfigured downlink        subframes, N is an integer greater than or equal to 2, a bit        quantity of a HARQ-ACK that needs to be fed back for each        downlink subframe in one subset of preconfigured downlink        subframes is a predetermined value, and bit quantities of hybrid        automatic repeat request-acknowledgements HARQ-ACKs that need to        be fed back for any downlink subframes in different subsets of        preconfigured downlink subframes are different;    -   receiving uplink control information that is sent by the        terminal in the uplink subframe and that is used for feeding        back a receiving status of the downlink data scheduled by the        downlink scheduling information; and    -   obtaining a HARQ-ACK codebook by decoding the received uplink        control information, where the obtained HARQ-ACK codebook        includes at least one sub-codebook, the at least one        sub-codebook is in one-to-one correspondence with at least one        subset of preconfigured downlink subframes, the at least one        subset of preconfigured downlink subframes is at least one of        the N subsets of preconfigured downlink subframes, and the at        least one subset of preconfigured downlink subframes is a subset        including downlink subframes in which the downlink data        scheduled by the downlink scheduling information is sent.

According to a fifth aspect, an embodiment of the present disclosureprovides a wireless communications system, including: an access networkdevice and a terminal; where

-   -   the access network device is configured to: send downlink        scheduling information of a downlink subframe F(i, j) to the        terminal, and send, to the terminal in the downlink subframe        F(i, j), downlink data scheduled by the downlink scheduling        information, where the downlink subframe F(i, j) is a subframe        in a set M of preconfigured downlink subframes corresponding to        an uplink subframe; where    -   F(i, j) represents a downlink subframe j on a carrier i        configured for the terminal, iϵC, C is a set of all carriers        configured for the terminal for downlink data transmission,    -   jϵK, and K is a set of downlink subframes corresponding to the        uplink subframe; and the set M of preconfigured downlink        subframes is divided into N subsets of preconfigured downlink        subframes, N is an integer greater than or equal to 2, a bit        quantity of a HARQ-ACK that needs to be fed back for each        downlink subframe in one subset of preconfigured downlink        subframes is a predetermined value, and bit quantities of hybrid        automatic repeat request-acknowledgements HARQ-ACKs that need to        be fed back for any downlink subframes in different subsets of        preconfigured downlink subframes are different;    -   the terminal is configured to: receive the downlink scheduling        information of the downlink subframe F(i, j); receive, in the        downlink subframe F(i, j), the downlink data scheduled by the        downlink scheduling information; generate a HARQ-ACK codebook        according to a receiving status of the downlink data received in        the downlink subframe F(i, j) and a bit quantity of a HARQ-ACK        that needs to be fed back for the downlink subframe F(i, j);        generate uplink control information by encoding the HARQ-ACK        codebook; and send the generated uplink control information in        the uplink subframe; where    -   the HARQ-ACK codebook includes at least one sub-codebook, the at        least one sub-codebook is in one-to-one correspondence with at        least one subset of preconfigured downlink subframes, the at        least one subset of preconfigured downlink subframes is at least        one of the N subsets of preconfigured downlink subframes, and        the at least one subset of preconfigured downlink subframes is a        subset including downlink subframes in which the downlink data        scheduled by the downlink scheduling information is sent; and    -   the access network device is further configured to: receive        uplink control information that is sent by the terminal in the        uplink subframe and that is used for feeding back the receiving        status of the downlink data scheduled by the downlink scheduling        information, and obtain the HARQ-ACK codebook by decoding the        received uplink control information.

In the embodiments of the present disclosure, the set M of preconfigureddownlink subframes is divided into the foregoing N subset ofpreconfigured downlink subframes, the bit quantity of the HARQ-ACK thatneeds to be fed back for each downlink subframe in one subset ofpreconfigured downlink subframes is a predetermined value, and the bitquantities of the HARQ-ACKs that need to be fed back for any downlinksubframes in different subsets of preconfigured downlink subframes aredifferent. In this way, when generating an ACK/NACK codebook, theterminal feeds back a HARQ-ACK according to the bit quantity of theHARQ-ACK that needs to be fed back for the downlink subframe in thesubset of preconfigured downlink subframes. Therefore, when the accessnetwork device parses, after receiving the uplink control informationgenerated according to the HARQ-ACK codebook, the ACK/NACK codebookaccording to the bit quantity of the HARQ-ACK that needs to be fed backfor the downlink subframe in the subset of preconfigured downlinksubframes, a HARQ-ACK feedback solution is provided, so that a case inwhich bit quantities of HARQ-ACKs that need to be fed back for downlinksubframes on different to-be-aggregated carriers are different can besupported.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a data transmission manner between UEand an access network device in a current CA mode;

FIG. 2A is a schematic structural diagram of a first wirelesscommunications system according to Embodiment 1 of the presentdisclosure and a third wireless communications system according toEmbodiment 3 of the present disclosure;

FIG. 2B is a schematic structural diagram of a second wirelesscommunication system according to Embodiment 2 of the presentdisclosure;

FIG. 3 is a flowchart of data transmission between an access networkdevice and a terminal in a first wireless communications systemaccording to Embodiment 1 of the present disclosure;

FIG. 4 is a flowchart of data transmission between an access networkdevice and a terminal in a second wireless communications systemaccording to Embodiment 2 of the present disclosure and a third wirelesscommunications system according to Embodiment 3 of the presentdisclosure;

FIG. 5A to FIG. 5D are schematic diagrams of first indicationinformation and second indication information in Embodiment 2 of thepresent disclosure;

FIG. 6 is a schematic diagram of a case in which a terminal cannotdetermine how to fill in a NACK in Embodiment 2 of the presentdisclosure;

FIG. 7A to FIG. 7B are schematic diagrams of first indicationinformation and second indication information in Embodiment 3 of thepresent disclosure;

FIG. 8 is a schematic diagram of a case in which a terminal cannotdetermine how to fill in a NACK according to an embodiment of thepresent disclosure;

FIG. 9 is a schematic structural diagram of a terminal according toEmbodiment 4 of the present disclosure;

FIG. 10 is a schematic structural diagram of an optional implementationof a terminal according to Embodiment 4 of the present disclosure;

FIG. 11 is a schematic structural diagram of another optionalimplementation of a terminal according to Embodiment 4 of the presentdisclosure;

FIG. 12 is a schematic structural diagram of an access network deviceaccording to Embodiment 5 of the present disclosure;

FIG. 13 is a schematic structural diagram of an optional implementationof an access network device according to Embodiment 5 of the presentdisclosure;

FIG. 14 is a schematic structural diagram of another optionalimplementation of an access network device according to Embodiment 5 ofthe present disclosure;

FIG. 15 is a flowchart of an uplink control information sending methodaccording to an embodiment of the present disclosure; and

FIG. 16 is a flowchart of an uplink control information receiving methodaccording to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure provide a terminal, an accessnetwork device, a wireless communications system, and an uplink controlinformation transmission method, to support a case in which bitquantities of HARQ-ACKs that need to be fed back for downlink subframeson different to-be-aggregated carriers are different.

In the embodiments of the present disclosure, the access network devicesends downlink scheduling information of a downlink subframe F(i, j) tothe terminal, and sends downlink data scheduled by the downlinkscheduling information. The downlink subframe F(i, j) is a subframe in aset M of preconfigured downlink subframes corresponding to an uplinksubframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a HARQ-ACK that needs to be fed back foreach downlink subframe in one subset of preconfigured downlink subframesis a predetermined value, and bit quantities of HARQ-ACKs that need tobe fed back for any downlink subframes in different subsets ofpreconfigured downlink subframes are different.

The terminal receives the downlink scheduling information of thedownlink subframe F(i, j), and receives, in the downlink subframe F(i,j), the downlink data scheduled by the downlink scheduling information.The terminal generates a HARQ-ACK codebook according to a receivingstatus of the downlink data received in the downlink subframe F(i, j)and a bit quantity of a HARQ-ACK that needs to be fed back for thedownlink subframe F(i, j).

The generated HARQ-ACK codebook includes at least one sub-codebook, theincluded at least one sub-codebook is in one-to-one correspondence withat least one subset of preconfigured downlink subframes, the at leastone subset of preconfigured downlink subframes is at least one of the Nsubsets of preconfigured downlink subframes, and the at least one subsetof preconfigured downlink subframes is a subset including downlinksubframes in which the downlink scheduling information is sent by theaccess network device.

The terminal generates uplink control information by encoding theHARQ-ACK codebook, and sends the generated uplink control information inthe uplink subframe.

The access network device receives the uplink control information sentby the terminal, and obtains the HARQ-ACK codebook by decoding thereceived uplink control information.

The set M of preconfigured downlink subframes is divided into theforegoing N subset of preconfigured downlink subframes, the bit quantityof the HARQ-ACK that needs to be fed back for each downlink subframe inone subset of preconfigured downlink subframes is a predetermined value,and the bit quantities of the HARQ-ACKs that need to be fed back for anydownlink subframes in different subsets of preconfigured downlinksubframes are different. In this way, when generating an ACK/NACKcodebook, the terminal feeds back a HARQ-ACK according to the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe in the subset of preconfigured downlink subframes. Therefore,when the access network device parses, after receiving the uplinkcontrol information generated according to the HARQ-ACK codebook, theACK/NACK codebook according to the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe in the subset ofpreconfigured downlink subframes, a HARQ-ACK feedback solution isprovided, so that a case in which bit quantities of HARQ-ACKs that needto be fed back for downlink subframes on different to-be-aggregatedcarriers are different can be supported.

For ease of understanding of the embodiments of the present disclosure,basic concepts used in the embodiments of the present disclosure aredescribed below.

For ease of understanding, an LTE system is used as an example fordescription, but this does not mean that the embodiments of the presentdisclosure are only applicable to the LTE system. Actually, a HARQ-ACKfeedback solution provided in the embodiments of the present disclosurecan be used for any wireless communications system in which a pluralityof carriers are provided for a same terminal for data transmission andbit quantities of feedback information corresponding to downlinksubframes on different carriers are different.

1. Data Transmission in the LTE System

In the LTE system, downlink transmission, that is, transmission from anaccess network device such as a base station to UE, is based on anorthogonal frequency division multiple access (OFDMA) manner, and uplinktransmission, that is, transmission from the UE to the access networkdevice, is based on a single carrier frequency division multiple access(SC-FDMA) manner.

For the downlink transmission, time-frequency resources are divided intoOFDM symbols in a time-domain dimension and subcarriers in afrequency-domain dimension, and for the uplink transmission,time-frequency resources are divided into SC-FDMA symbols in afrequency-domain dimension. In the embodiments of the presentdisclosure, the OFDM symbol and the SC-FDMA symbol are collectivelyreferred to as a “time-domain symbol”.

In the LTE system, a minimum resource granularity is referred to as aresource element (RE) that represents a time-frequency lattice pointincluding a time-domain symbol in a time domain and a subcarrier in afrequency domain.

Generally, a basic time unit used by the access network device forscheduling is a subframe, and one subframe includes a plurality oftime-domain symbols. Alternatively, for some scenarios in which atransmission delay needs to be reduced, a basic time unit used by theaccess network device for scheduling may be one or more time-domainsymbols.

A specific scheduling process is: The access network device sends acontrol channel such as a physical downlink control channel (PDCCH) oran enhanced physical downlink control channel (EPDCCH), where thecontrol channel may carry scheduling information of a PDSCH or a PUSCH,and the scheduling information includes control information such asresource allocation information or a modulation and coding manner; andthe UE receives the control channel in a subframe, and receives adownlink data channel or sends an uplink data channel according to thescheduling information carried in the received control channel.

The LTE system supports a frequency division duplex (FDD) manner and atime division duplex (TDD) manner. For an LTE system using the FDDmanner, which is briefly referred to as an FDD LTE system, differentcarriers are used for downlink transmission and uplink transmission. Foran LTE system using the TDD manner, which is briefly referred to as aTDD LTE system, different times of a same carrier are used for uplinktransmission and downlink transmission, and a carrier specificallyincludes a downlink subframe, an uplink subframe, and a specialsubframe.

The special subframe includes three parts: a downlink pilot timeslot(DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS). TheGP is mainly used as a downlink-to-uplink component conversion time andcompensation for a downlink-to-uplink propagation delay. In addition,downlink data can be transmitted in the DwPTS, and a PUSCH cannot betransmitted in the UpPTS. Therefore, from this perspective, the specialsubframe may be considered as a downlink subframe.

2. HARQ-ACK Time Sequence Relationship

In the FDD LTE system, after receiving a PDSCH in a subframe n−4, the UEfeeds back a HARQ-ACK in a subframe n. In the TDD LTE system, a timesequence relationship between PDSCH receiving and HARQ-ACK feedbackcorresponding to the PDSCH receiving is shown in Table 2. A subframemarked with a number is an uplink subframe n used for feeding back aHARQ-ACK, and the marked number indicates that a HARQ-ACK correspondingto a PDSCH in a set of downlink subframes n-k (k belongs to K) needs tobe fed back in the uplink subframe n. For example, K={7, 6} in asubframe n=2 in an uplink-downlink configuration 1 indicates that theuplink subframe n=2 is used for feeding back HARQ-ACKs corresponding toPDSCHs in two downlink subframes n−7 and n−6, and specifically, n−7 is adownlink subframe 5 and n−6 is a downlink subframe 6.

TABLE 2 Time sequence relationship between a PDSCH and a correspondingHARQ-ACK in a TDD LTE system Uplink-downlink Subframe number nconfiguration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 — — 6 — 4 1 — — 7, 6 4 — —— 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4, 6 — — 3 — — 7, 6, 11 6, 55, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 — — — — — — 5 — — 13, 12,9, 8, — — — — — — — 7, 5, 4, 11, 6 6 — — 7 7 5 — — 7 7 —

3. TDD Uplink-Downlink Configuration in the LTE System

The LTE system currently supports seven types of different TDDuplink-downlink configurations, and the uplink-downlink configurationsare the first column of Table 2. As shown in Table 3, D represents adownlink subframe, S represents a special subframe, and U represents anuplink subframe.

TABLE 3 Different TDD uplink-downlink configurations in the LTE systemUplink- Downlink- downlink to-uplink config- switch-point Subframenumber uration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U D S U UU 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  D S U UU D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D D D D D 65 ms D S U U U D S U U D

4. Carrier Aggregation Supported by the LTE System

The LTE system supports FDD CA, TDD CA, and FDD+TDD CA. TDD CA isfurther classified into TDD CA with a same uplink-downlink configurationand TDD CA with different uplink-downlink configurations. There is oneprimary component carrier and at least one secondary component carrierin a CA mode, and a PUCCH carrying a HARQ-ACK can be sent only on anuplink primary component carrier configured on the UE. A current PUCCHformat supports transmission of a HARQ-ACK of a maximum of 22 bits.

5. Set M of Preconfigured Downlink Subframes

The set M of preconfigured downlink subframes is corresponding to anuplink subframe on a primary component carrier in CA.

A downlink subframe F(i,j)ϵM, iϵC, C is a set of all carriers configuredfor a terminal for downlink data transmission, JϵK, K is a set ofdownlink subframes corresponding to an uplink subframe according to theHARQ-ACK time sequence relationship, and the time sequence relationshipmay be the time sequence relationship that is shown in Table 2 and thatis between a PDSCH and a corresponding HARQ-ACK in the TDD LTE system.

The current LTE system supports a case of configuring a maximum of fivecarriers for one UE for carrier aggregation. A most typical TDDuplink-downlink configuration 2 is used as an example. A set M ofpreconfigured downlink subframes corresponding to or associated with anuplink subframe 2 on an uplink primary component carrier includessubframes 4, 5, 6, and 8 on the five carriers, that is, 20 downlinksubframes in total.

For simple description, the special subframe is considered as a downlinksubframe. A meaning of the “corresponding to or associated with”mentioned herein may be understood as: All HARQ-ACKs corresponding toPDSCHs in the foregoing 20 downlink subframes are fed back in the uplinksubframe 2, and this may be specifically determined according to thetime sequence relationship that is in Table 2 and that is between aPDSCH and a HARQ-ACK.

6. HARQ-ACK Codebook and HARQ-ACK Information

On a UE side, the HARQ-ACK codebook represents original HARQ-ACK bitstreams that exist before channel encoding, and the original bit streamsmay be sorted according to a specific sorting rule. These originalHARQ-ACK information bits may be bit streams of 1 or 0. “1” is an ACKindicating that downlink data is correctly received, and “0” is a NACKindicating that downlink data is not correctly received. The UE sends,to the access network device, HARQ-ACK information generated after theUE performs channel encoding on the HARQ-ACK codebook. On an accessnetwork device side, the access network device receives the HARQ-ACKinformation sent by the UE, and obtains the HARQ-ACK codebook afterperforming channel decoding on the HARQ-ACK information.

The configuring five carriers for one UE for carrier aggregation and theTDD uplink-downlink configuration 2 in the item 5 “set M ofpreconfigured downlink subframes” are still used as an example. TheHARQ-ACK codebook generated by the UE may be determined according to theset M of preconfigured downlink subframes. Specifically, carriers may besorted before subframes are sorted, that is, the foregoing sorting rulemay be carriers before subframes. For example, HARQ-ACK bitscorresponding to subframes 4, 5, 6, and 8 on a carrier 1 are arrangedbefore HARQ-ACK bits corresponding to subframes 4, 5, 6, and 8 on acarrier 2. In addition, for a location at which the UE fails to receivea subframe scheduled by the PDSCH, the UE needs to fill in a NACK.

7. Scenario in which the UE Needs to Feed Back, in One Uplink Subframe,a HARQ-ACK of a Relatively Large Bit Quantity

With further evolution of LTE technologies, feedback of a HARQ-ACK of aneven larger bit quantity may need to be supported in the future, and thebit quantity may be far greater than 22.

Scenario 1

CA of an even larger quantity of carriers is introduced, and is referredto as “super CA” for short.

For example, CA of ten carriers or even a maximum of 32 carriers is“super CA”. CA of ten carriers with the TDD uplink-downlinkconfiguration 2 is used as an example. In this case, a HARQ-ACK of 40bits needs to be fed back in an uplink subframe 2 on an uplink primarycomponent carrier.

Scenario 2

CA of five carriers is supported, but a plurality of carriers areconfigured as a TDD uplink-downlink configuration 5. For example, aprimary component carrier is the uplink-downlink configuration 2, andfour secondary component carriers are the uplink-downlink configuration5. In this case, a HARQ-ACK of 4+9×4=40 bits needs to be fed back in anuplink subframe 2 on an uplink primary component carrier.

A possible solution is: introducing a PUCCH format that supportstransmission with an even larger bit capacity. In consideration of acase in which this new PUCCH format needs to support an even largerquantity of HARQ-ACK bits, for example, 128 HARQ-ACK bits may besupported in configuration of the TDD uplink-downlink configuration 2 of32 carriers, introduction of the new format increases uplink controlchannel overheads.

An optional solution in the embodiments of the present disclosure may beapplied to the foregoing scenario in which the UE needs to feed back, inone uplink subframe, a HARQ-ACK of a relatively large bit quantity, sothat a bit quantity of a HARQ-ACK that needs to be fed back by the UEcan be effectively reduced.

8. A Communications Standard, a Terminal, and an Access Network Deviceto which the Embodiments of the Present Disclosure are Applicable

Communications standards of various wireless communications systemsprovided in the embodiments of the present disclosure include but arenot limited to Global System for Mobile Communications (GSM), CodeDivision Multiple Access (CDMA) IS-95, Code Division Multiple Access(CDMA) 2000, Time Division-Synchronous Code Division Multiple Access(TD-SCDMA), Wideband Code Division Multiple Access (WCDMA), TimeDivision Duplex-Long Term Evolution (TDD LTE), Frequency DivisionDuplex-Long Term Evolution (FDD LTE), Long Term Evolution-Advanced(LTE-advanced), a personal handyphone system (PHS), Wireless Fidelity(WiFi) stipulated in the 802.11 series of protocols, WorldwideInteroperability for Microwave Access (WiMAX), and various evolvedwireless communications systems in the future.

The embodiments of the present disclosure can be used for any wirelesscommunications system in which bit quantities of feedback informationcorresponding to different carriers are different because a plurality ofcarriers are provided for a same terminal for data transmission and thedifferent carriers have different transmission modes. Therefore, theterminal correctly sends the HARQ-ACK information, and the accessnetwork device can accurately learn a downlink data receiving status ofthe terminal according to the received HARQ-ACK information.

The terminal in the embodiments of the present disclosure may be awireless terminal. The wireless terminal may be a device that provides avoice and/or data connectivity for a user, a handheld device with awireless connection function, or another processing device connected toa wireless modem. The wireless terminal may communicate with one or morecore networks by using a radio access network (for example, RAN). Thewireless terminal may be a mobile terminal such as a mobile phone (orreferred to as a “cellular” phone) or a computer with a mobile terminal.For example, the wireless terminal may be a portable, pocket-sized,handheld, computer built-in, or in-vehicle mobile apparatus thatexchanges a voice and/or data with the radio access network. Forexample, the wireless terminal is a device such as a personalcommunication service (PCS) phone, a cordless phone, a SessionInitiation Protocol (SIP) phone, a wireless local loop (WLL) station, ora personal digital assistant (PDA). The wireless terminal may also bereferred to as a system, a subscriber unit, a subscriber station, amobile station, a mobile terminal (Mobile), a remote station, an accesspoint, a remote terminal, an access terminal, a user terminal, a useragent, a user device, or user equipment.

The access network device provided in the embodiments of the presentdisclosure may include a base station, a wireless resource managementdevice configured to control a base station, or a base station and awireless resource management device configured to control the basestation. The access network device may be a macro station or a smallstation, and the terminal is a terminal device that communicates withthe access network device.

For example, for an LTE system such as TDD LTE, FDD LTE, or LTE-A, theaccess network device in the wireless communications system provided inthe embodiments of the present disclosure may be an evolved NodeB(eNodeB), and the terminal may be UE. For a TD-SCDMA system or a WCDMAsystem, the access network device in the wireless communications systemprovided in the embodiments of the present disclosure may include aNodeB and/or a radio network controller (RNC), and the terminal may beUE. For a GSM system, the access network device provided in theembodiments of the present disclosure may include a base transceiverstation (BTS) and/or a base station controller (BSC), and the terminalis a mobile station (MS). For a WiFi system, the access network devicemay include an access point (AP) and/or an access controller (AC), andthe terminal may be a station (STA).

9. Other Descriptions

In addition, the terms “system” and “network” may be usually usedinterchangeably in this specification. The term “and/or” in thisspecification describes only an association relationship for describingassociated objects and represents that three relationships may exist.For example, A and/or B may represent the following three cases: Only Aexists, both A and B exist, and only B exists. In addition, thecharacter “/” in this specification generally indicates an “or”relationship between associated objects.

Basic concepts in the embodiments of the present disclosure aredescribed above. For ease of understanding, the embodiments of thepresent disclosure are described in detail below with reference to theaccompanying drawings. For clarity of description, the embodiments ofthe present disclosure are listed in Table 4.

TABLE 4 List of embodiments of the present disclosure Embodiment Briefdescription Embodiment 1 First wireless communications system (A set Mof preconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframes.) Embodiment 2 Second wirelesscommunications system (A HARQ-ACK is fed back for a scheduled downlinksubframe; whether downlink scheduling information is undetected isdetermined; and if the downlink scheduling information is undetected, aNACK is filled in for a HARQ-ACK at an undetected location.) Embodiment3 Third wireless communications system (A set M of preconfigureddownlink subframes is divided into N subsets of preconfigured downlinksubframes; a HARQ-ACK is fed back for a scheduled downlink subframe;whether downlink scheduling information is undetected is determined; andif the downlink scheduling information is undetected, a NACK is filledin for a HARQ-ACK at an undetected location.) Embodiment 4 Accessnetwork device Embodiment 5 Terminal Embodiment 6 Uplink controlinformation sending method Embodiment 7 Uplink control informationreceiving method

The embodiments of the present disclosure are described in detail below.

Embodiment 1

As shown in FIG. 2A, a first wireless communications system provided inEmbodiment 1 of the present disclosure includes an access network device201 and a terminal 202.

The access network device 201 is configured to: send downlink schedulinginformation of a downlink subframe F(i, j) to the terminal 202, andsend, in the downlink subframe F(i, j), downlink data scheduled by thedownlink scheduling information. The downlink subframe F(i, j) is asubframe in a set M of preconfigured downlink subframes corresponding toan uplink subframe, for example, a subframe in a preconfigured downlinksubframe M corresponding to one uplink subframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a HARQ-ACK that needs to be fed back foreach downlink subframe in one subset of preconfigured downlink subframesis a predetermined value, and bit quantities of HARQ-ACKs that need tobe fed back for any downlink subframes in different subsets ofpreconfigured downlink subframes are different.

The terminal 202 is configured to: receive the downlink schedulinginformation of the downlink subframe F(i, j); receive, in the downlinksubframe F(i, j), the downlink data scheduled by the downlink schedulinginformation; generate a HARQ-ACK codebook according to a receivingstatus of the downlink data received in the downlink subframe F(i, j)and a bit quantity of a HARQ-ACK that needs to be fed back for thedownlink subframe F(i, j); generate uplink control information byencoding the generated HARQ-ACK codebook; and send the generated uplinkcontrol information in the uplink subframe.

The HARQ-ACK codebook generated by the terminal 202 includes at leastone sub-codebook, the included at least one sub-codebook is inone-to-one correspondence with at least one subset of preconfigureddownlink subframes, the at least one subset of preconfigured downlinksubframes is at least one of the N subsets of preconfigured downlinksubframes, and the at least one subset of preconfigured downlinksubframes is a subset including downlink subframes in which the downlinkscheduling information is sent by the access network device 201.

The access network device 201 is further configured to: receive theuplink control information sent by the terminal 202, and obtain theHARQ-ACK codebook after decoding the received uplink controlinformation.

A process of downlink scheduling, downlink data transmission, andHARQ-ACK information feedback between the access network device 201 andthe terminal 202 is described below with reference to FIG. 3. Theprocess includes the following steps:

S301. The access network device 201 sends downlink schedulinginformation of a downlink subframe F(i, j) to the terminal 202.

S302. The terminal 202 receives the downlink scheduling information.

S303. The access network device 201 sends, in the downlink subframe F(i,j), downlink data scheduled by the downlink scheduling information sentin step S301.

S304. The terminal 202 receives, in the downlink subframe F(i, j)according to the downlink scheduling information received in step S302,the downlink data scheduled by the downlink scheduling information.

S305. The terminal 202 generates a HARQ-ACK codebook according to areceiving status of the downlink data received in the downlink subframeF(i, j) and a bit quantity of a HARQ-ACK that needs to be fed back forthe downlink subframe F(i, j), and generates uplink control informationby encoding the generated HARQ-ACK codebook.

S306. The terminal 202 sends the generated uplink control information tothe access network device 201.

S307. The access network device 201 obtains the HARQ-ACK codebook afterdecoding the received uplink control information, and determines,according to the obtained HARQ-ACK codebook, the receiving status of thedownlink data in the downlink subframe F(i, j) that is scheduled in aset M of preconfigured downlink subframes.

Step S301 and step S303 may be completed in a same step. For example,for an LTE system, the access network device 201 sends, in a samedownlink subframe used for sending the downlink scheduling information,the downlink data scheduled by the downlink scheduling information. Inthis case, step S302 and step S304 may also be completed in a same step.The terminal 202 may receive downlink data in a downlink subframeaccording to received downlink scheduling information in the samedownlink subframe.

In addition, to send downlink scheduling information in a downlinksubframe m and schedule the terminal to receive downlink data that is ina downlink subframe m+1, the access network device 201 may use a mannershown in FIG. 3: sending the scheduling information before sending thedownlink data. Accordingly, the terminal 202 receives the downlinkscheduling information first, and then receives the downlink dataaccording to the received downlink scheduling information.Alternatively, a case in which downlink scheduling information is sentin a downlink subframe m on a carrier 1 and the terminal is scheduled toreceive downlink data that is in a downlink subframe m on a carrier 2 isequivalent to that the downlink scheduling information and the downlinkdata scheduled by the downlink scheduling information are sent andreceived in a downlink subframe at a same moment, but the downlinkscheduling information and the downlink data scheduled by the downlinkscheduling information are on different carriers.

A process and an implementation scheme shown in FIG. 3 are described indetail below.

1. Step S301. The access network device 201 sends the downlinkscheduling information.

In this embodiment of the present disclosure, in step S301, the accessnetwork device 201 sends the downlink scheduling information of thedownlink subframe F(i, j). The downlink subframe F(i, j) is a subframein a set M of preconfigured downlink subframes corresponding to anuplink subframe, F(i, j) represents a downlink subframe j on a carrier iconfigured for the terminal 202, iϵC, C is a set of all carriersconfigured for the terminal 202 for downlink data transmission, jϵK, andK is a set of downlink subframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes may be all downlinksubframes on all aggregated carriers corresponding to one uplinksubframe according to a HARQ-ACK time sequence relationship, forexample, a time sequence relationship that is defined in Table 2 andthat is between a PDSCH and a corresponding HARQ-ACK. That is, theterminal 202 feeds back, in the uplink subframe according to the definedHARQ-ACK time sequence relationship, a HARQ-ACK for receiving ofdownlink data in each downlink subframe in the set M of preconfigureddownlink subframes.

In a CA mode, the access network device 201 configures a plurality ofcarriers for the terminal 202. For example, a plurality of carriers areconfigured by using radio resource control (Radio Resource Control, RRC)signaling, the plurality of carriers may be FDD carriers or TDDcarriers, and each carrier includes a plurality of downlink subframes.For the TDD carrier, different carriers may have a same uplink-downlinkconfiguration or different uplink-downlink configurations.

For example, ten TDD carriers with a same uplink-downlink configuration2 are configured for the terminal 202. According to the TDDuplink-downlink subframe configurations in Table 2 and the time sequencerelationship that is in Table 1 and that is between downlink data and anuplink HARQ-ACK, HARQ-ACKs corresponding to downlink data channels indownlink subframes 4, 5, 6, and 8 on a maximum of the foregoing tencarriers need to be fed back in an uplink subframe 2 on a primarycomponent carrier.

These downlink subframes, that is, the downlink data channels in thesedownlink subframes may be separately scheduled by using independentdownlink control channels, or may be scheduled by using a unifieddownlink control channel, or may be scheduled by using a combinationthereof. For example, a downlink data channel in at least one downlinksubframe is scheduled by each of a plurality of downlink controlchannels. In this embodiment of the present disclosure, scheduling byusing independent downlink control channels is used as an example fordescription.

The downlink subframe mentioned herein includes a common downlinksubframe and also includes a special subframe in a TDD system. After aplurality of carriers are configured for the terminal 202, the accessnetwork device 201 may send a downlink control channel, to scheduledownlink data channels in downlink subframes on these configuredcarriers. Further, the terminal 202 needs to feed back uplink HARQ-ACKscorresponding to these downlink data channels.

For example, the terminal 202 feeds back a HARQ-ACK in an uplinksubframe 2. According to a time sequence relationship that is in a TDDconfiguration 2 and that is between a downlink data channel and anuplink HARQ-ACK, a set M of preconfigured downlink subframes associatedwith the uplink subframe 2 includes: 40 downlink subframes, that is, asubframe 4, a subframe 5, a subframe 6, and a subframe 8 on carriers 1to 10. That is, a HARQ-ACK that needs to be fed back by the terminal 202in an uplink subframe 2 on a primary component carrier in carrieraggregation is corresponding to a downlink data channel in the set M ofpreconfigured downlink subframes.

The terminal 202 may receive the downlink control channel in the set Mof preconfigured downlink subframes, for example, the terminal 202 mayreceive downlink control channels in all downlink subframes in the setof preconfigured downlink subframes, or may receive downlink controlchannels in some subframes in the set of preconfigured downlinksubframes. Then, the terminal 202 further receives, according to thereceived downlink control channels, downlink data channels scheduled bythese downlink control channels.

The downlink control channel and the downlink data channel scheduled bythe downlink control channel are usually in a same subframe.Alternatively, as described above, the downlink control channel and thedownlink data channel scheduled by the downlink control channel may bein different subframes provided that a correspondence between thedownlink control channel and the downlink data channel scheduled by thedownlink control channel can be identified. For example, a time sequencerelationship between the two channels is pre-specified, the accessnetwork device 201 sends the downlink control channel and the downlinkdata channel according to the pre-specified time sequence relationship,and the terminal 202 receives the downlink control channel and thedownlink data channel according to the pre-specified time sequencerelationship.

Herein, a downlink subframe subset that is of the set M of preconfigureddownlink subframes of the terminal 202 and in which an actuallyscheduled downlink data channel is located is referred to as an“instantly scheduled downlink subframe set”, and the instantly scheduleddownlink subframe set is a subset of the set M of preconfigured downlinksubframes.

The downlink data channel in the scheduled downlink subframe may includea first downlink data channel scheduled by a downlink control channel,that is, a dynamically scheduled downlink data channel, or may include asecond downlink data channel that is not scheduled by a downlink controlchannel, for example, a downlink data channel used for semi-persistentscheduling (SPS). Usually, after an SPS mechanism of a terminal isactivated, a downlink data channel used for SPS does not requiredownlink control and scheduling during initial transmission of a HARQ,but the downlink data channel used for the SPS is directly sent at apreconfigured period such as 20 ms.

In addition, the access network device 201 may further send a separatespecial downlink control channel. In an LTE system, the downlink controlinformation may be a PDCCH, and the special downlink control channeldoes not schedule a downlink data channel but is used for instructing toterminate or release the SPS mechanism. However, a corresponding uplinkHARQ-ACK also needs to be fed back for the special downlink controlchannel. Therefore, optionally, a subframe that is in the set ofpreconfigured downlink subframes and that is used for transmitting thespecial downlink control channel may also be placed in the instantlyscheduled downlink subframe set, and the terminal 202 may also feed backa corresponding HARQ-ACK for the subframe.

2. Step S302. The terminal 202 receives the downlink schedulinginformation.

In step S302, the terminal 202 receives the downlink schedulinginformation sent by the access network device 201. As described above,the downlink scheduling information may include control information suchas resource allocation information or a modulation and coding manner.The terminal 202 learns, according to the received downlink schedulinginformation, information such as information about a resource allocatedfor downlink data transmission and a modulation and coding manner ofdownlink data, and the terminal 202 receives the downlink data accordingto the learned information.

However, due to a time-varying characteristic of a radio channel, theterminal 202 may fail to receive downlink scheduling information whenthe radio channel is of poor quality. In this case, the terminal 202cannot obtain the downlink scheduling information, and cannot receivethe downlink data according to the downlink scheduling information.

Optionally, if the access network device 201 sends the foregoing specialdownlink control channel to the terminal 202, and as described above,the special downlink control channel is used for instructing toterminate or release the SPS mechanism, the terminal 202 further needsto receive the special downlink control channel.

3. Step S303. The access network device 201 sends the downlink data inthe downlink subframe F(i, j).

After sending the downlink scheduling information, the access networkdevice 201 sends the downlink data in the downlink subframe F(i, j)according to the control information such as the resource allocationinformation or the modulation and coding manner in the downlinkscheduling information.

4. Step S304. The terminal 202 receives the downlink data.

The terminal 202 receives the downlink data in the downlink subframeF(i, j) according to the downlink scheduling information received instep S302. If the terminal 202 fails to receive the downlink schedulinginformation of the downlink subframe F(i, j) in step S302, the terminal202 does not receive the downlink data in the downlink subframe F(i, j)in step S304.

5. Division of the Set M of Preconfigured Downlink Subframes

The set M of preconfigured downlink subframes may be divided into Nsubsets of preconfigured downlink subframes, N is an integer greaterthan or equal to 2, and a bit quantity of a HARQ-ACK that needs to befed back by the terminal 202 for each downlink subframe in the subset ofpreconfigured downlink subframes is a predetermined value.

Both the terminal 202 and the access network device 201 need to know adivision rule of the set M of preconfigured downlink subframes inadvance, and the rule is the same for the terminal 202 and the accessnetwork device 201. The terminal 202 generates an ACK/NACK codebookaccording to the same division rule, and the access network device 201parses the ACK/NACK codebook according to the same rule, so as toaccurately learn a downlink data receiving status of the terminal 202.Alternatively, the access network device 201 determines the foregoingrule and then notifies the terminal of the rule, that is, the accessnetwork device and the terminal have consistent understanding of theforegoing rule.

For example, both the terminal 202 and the access network device 201need to know a value of N and a subset of preconfigured downlinksubframes to which a downlink subframe in the set M of preconfigureddownlink subframes belongs, and know a bit quantity of a HARQ-ACK thatneeds to be fed back for a downlink subframe in each subset ofpreconfigured downlink subframes. For example, both the access networkdevice 201 and the terminal 202 may determine, according to a datachannel transmission mode of a downlink subframe, a bit quantity of aHARQ-ACK that needs to be fed back for the downlink subframe, anddetermine a subset of preconfigured downlink subframes to which thedownlink subframe belongs. In this way, the terminal 202 correctly fillsin a HARQ-ACK bit and generates a HARQ-ACK codebook according to thedetermined bit quantity of the HARQ-ACK and the determined subset ofpreconfigured downlink subframes to which the downlink subframe belongs.The access network device 201 parses the HARQ-ACK codebook according toa same rule, so that the access network device 201 can accurately learnthe receiving status of the downlink data.

That the terminal 202 feeds back a HARQ-ACK in an uplink subframe isstill used as an example. Data channel transmission modes on all the tencarriers configured for the terminal 202 may be the same or different.It is assumed that two different data channel transmission modes areconfigured, each PDSCH in a first data channel transmission mode isconfigured to correspond to one transport block, that is, correspond toone HARQ-ACK bit, and each PDSCH in a second data channel transmissionmode is configured to correspond to two transport blocks, that is,correspond to two HARQ-ACK bits.

It should be noted that, for a carrier, the access network device 201may perform configuration, so that the terminal uses a transmission modewith two transport blocks, that is, two transport blocks may betransmitted in each downlink subframe on the carrier, and therefore eachdownlink subframe corresponds to two HARQ-ACK bits. In this case, thedownlink subframe on the carrier needs to be classified into a group oftwo HARQ-ACK bits. However, the access network device 201 may furtherperform configuration, so that the terminal 202 feeds back a HARQ-ACKfor two transport blocks in a downlink subframe in a HARQ-ACK spacebinding mode, and in this case, two transport blocks scheduled in adownlink subframe correspond to only one HARQ-ACK bit, that is, an ACKof one bit is fed back only when both the two transport blocks arecorrectly received, and otherwise, a NACK of one bit is fed back. Inthis case, one downlink subframe including two transport blockscorresponds to feedback of one HARQ-ACK bit. Therefore, the downlinksubframe on the carrier needs to be classified into a group of oneHARQ-ACK bit. Alternatively, the downlink subframe on the carrier isclassified into another group of one HARQ-ACK bit, that is, the group,obtained after space binding, of one HARQ-ACK bit and the group in whichone transport block corresponds to one HARQ-ACK bit are two independentgroups.

As described above, when UE fails to receive the downlink schedulinginformation, because different transmission modes are configured fordifferent carriers, the UE cannot determine a quantity of bits to befilled in a HARQ-ACK.

There may be a plurality of optional solutions to this problem, and twosolutions are used as examples below for description.

Optional Solution 1

In this solution, the set M of preconfigured downlink subframes may bedivided into N subsets of preconfigured downlink subframes. N is aninteger greater than or equal to 2, a bit quantity of a hybrid automaticrepeat request-acknowledgement HARQ-ACK that needs to be fed back by theterminal 202 for each downlink subframe in the subset of preconfigureddownlink subframes is a predetermined value such as 1 bit or 2 bits, andbit quantities of HARQ-ACKs that need to be fed back for any downlinksubframes in different downlink subframes are different.

In this case, a quantity of subsets of preconfigured downlink subframesdepends on a quantity of possible values of a bit quantity of a HARQ-ACKthat needs to be fed back. For example, if a bit quantity of a HARQ-ACKthat needs to be fed back for the set M of preconfigured downlinksubframes has two different values, the set M of preconfigured downlinksubframes may be divided into two subsets of preconfigured downlinksubframes. For another example, if a bit quantity of a HARQ-ACK thatneeds to be fed back for the set M of preconfigured downlink subframeshas three different values, the set M of preconfigured downlinksubframes may be divided into three subsets of preconfigured downlinksubframes. Certainly, if a bit quantity of a HARQ-ACK that needs to befed back for the set M of preconfigured downlink subframes has only onevalue, the set M of preconfigured downlink subframes does not need to bedivided.

For example, N=2, and the set M of preconfigured downlink subframes isdivided into a first subset of preconfigured downlink subframes and asecond subset of preconfigured downlink subframes. Because an instantlyscheduled downlink subframe set is a subset of the set of preconfigureddownlink subframes, the instantly scheduled downlink subframe set isdivided into a first instantly scheduled downlink subframe subset and asecond instantly scheduled downlink subframe subset, the first instantlyscheduled downlink subframe subset is a subset of the first subset ofpreconfigured downlink subframes, and the second instantly scheduleddownlink subframe subset is a subset of the second subset ofpreconfigured downlink subframes.

For another example, if a bit quantity of a HARQ-ACK that needs to befed back for the set M of preconfigured downlink subframes has threedifferent values, the set M of preconfigured downlink subframes may bedivided into three subsets of preconfigured downlink subframes.Certainly, if a bit quantity of a HARQ-ACK that needs to be fed back forthe set M of preconfigured downlink subframes has only one value, theset M of preconfigured downlink subframes does not need to be divided.

Optional Solution 2

In this solution, the set M of preconfigured downlink subframes may bedivided into P subsets of preconfigured downlink subframes. P is aninteger greater than or equal to 2, and a bit quantity of a HARQ-ACKthat needs to be fed back by the terminal 202 for each downlink subframein the subset of preconfigured downlink subframes is a predeterminedvalue such as 1 bit or 2 bits. A difference from the optional solution 1is that it does not need to be defined that bit quantities of HARQ-ACKsthat need to be fed back for any downlink subframes in different subsetsof preconfigured downlink subframes are different.

The terminal 202 can correctly fill in a NACK provided that bitquantities of HARQ-ACKs that need to be fed back for downlink subframesin a same subset of preconfigured downlink subframes are the same.

In this case, a quantity of subsets of preconfigured downlink subframesis greater than or equal to a quantity of values of a bit quantity of aHARQ-ACK that needs to be fed back. For example, if a bit quantity of aHARQ-ACK that needs to be fed back for the set M of preconfigureddownlink subframes has two different values, the preconfigured downlinksubframe M may be divided into three or four subsets of preconfigureddownlink subframes or the like provided that bit quantities of HARQ-ACKsthat need to be fed back for downlink subframes in a same subset ofpreconfigured downlink subframes are the same.

The solution may be applied to the following scenario, to resolve aproblem of an insufficient uplink subframe capacity.

A capacity of one uplink subframe is usually limited, and when HARQ-ACKsfor a plurality of downlink subframes need to be fed back in a sameuplink subframe, load of the uplink subframe is relatively large.Currently, in a CA mode, a HARQ-ACK is sent in an uplink subframe on aprimary component carrier, and in consideration of a limited capacity ofthe uplink subframe on the primary component carrier, HARQ-ACKs for somedownlink subframes may be sent in an uplink subframe on a secondarycomponent carrier. In this case, downlink subframes that are in the setM of preconfigured downlink subframes and for which HARQ-ACKs that needto be fed back have a same bit quantity are further classified into aplurality of subsets of preconfigured downlink subframes, and somesubsets of preconfigured downlink subframes are sent in the downlinksubframe on the secondary component carrier, so that the problem of aninsufficient uplink subframe capacity of the primary component carrieris resolved. Optionally, the uplink subframe on the secondary componentcarrier and the uplink subframe on the primary component carrier have asame subframe number, so that a HARQ-ACK time sequence relationship doesnot need to be redefined.

The foregoing two optional solutions are merely examples. It can belearned from the foregoing two solutions that when the set M ofpreconfigured downlink subframes is divided into a plurality of subsetsof preconfigured downlink subframes, the terminal 202 can correctly fillin a NACK and the access network device 201 can correctly receive theHARQ-ACK provided that bit quantities of HARQ-ACKs that need to be fedback for downlink subframes in a same subset of preconfigured downlinksubframes are the same and are a predetermined value known to both theaccess network device 201 and the terminal 202.

6. In Step S305, the Terminal 202 Generates the HARQ-ACK Codebook.

The HARQ-ACK codebook generated by the terminal 202 may include HARQ-ACKbits of all subframes in the set M of preconfigured downlink subframes,or may include HARQ-ACK bits of all scheduled downlink subframes in theset M of preconfigured downlink subframes, that is, HARQ-ACK bits of alldownlink subframes in the foregoing instantly scheduled downlinksubframe set.

The terminal 202 may determine, based on the time sequence relationshipspecified in Table 2 and according to the receiving status of thedownlink data scheduled by the received downlink scheduling informationand the bit quantity of the HARQ-ACK that needs to be fed back for thedownlink subframe, an information bit of an original HARQ-ACK that needsto be fed back in the uplink subframe (for example, the foregoing uplinksubframe 2), to generate the HARQ-ACK codebook. Optionally, if theterminal 202 further receives the foregoing special downlink controlchannel in step S302, the terminal 202 may further perform thedetermining according to a receiving status of the special downlinkcontrol channel.

Optionally, the HARQ-ACK codebook may be corresponding to the foregoinginstantly scheduled downlink subframe set. The instantly scheduleddownlink subframe set includes a downlink subframe in which the accessnetwork device 201 schedules downlink data transmission, and if theaccess network device 201 further sends the special downlink controlchannel, the instantly scheduled downlink subframe set further includesa subframe in which the special downlink control channel is located. Inthe following embodiments, it is assumed that there is no specialdownlink control channel unless otherwise specified, but this embodimentof the present disclosure may be applied to a case in which there is adownlink data channel and a special downlink control channel.

As described above, in this embodiment of the present disclosure, if theset M of preconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframes, the HARQ-ACK codebook generated by theterminal 202 may include at least one sub-codebook, the at least onesub-codebook is in one-to-one correspondence with at least one subset ofpreconfigured downlink subframes, the at least one subset ofpreconfigured downlink subframes is at least one of the N subsets ofpreconfigured downlink subframes, and the at least one subset ofpreconfigured downlink subframes is a subset including the downlinksubframe in which the terminal receives the downlink schedulinginformation.

If the HARQ-ACK codebook generated by the terminal 202 includes only theHARQ-ACK bits of all the scheduled downlink subframes in the set M ofpreconfigured downlink subframes, that is, the HARQ-ACK bits of all thedownlink subframes in the instantly scheduled downlink subframe set,when no downlink subframe is scheduled in one or more of the N subsetsof preconfigured downlink subframes, or when the terminal 202 receivesno downlink scheduling information of any downlink subframe in one ormore of the N subsets of preconfigured downlink subframes, the HARQ-ACKcodebook generated by the terminal 202 may not include a HARQ-ACK bitcorresponding to a subset of preconfigured downlink subframes in whichno downlink subframe is scheduled.

If the HARQ-ACK codebook generated by the terminal 202 includes theHARQ-ACK bits of all the subframes in the set M of preconfigureddownlink subframes, when generating the HARQ-ACK codebook, the terminal202 may generate a sub-codebook corresponding to each of the N subsetsof preconfigured downlink subframes. Optionally, the terminal 202 mayform a HARQ-ACK codebook by cascading N generated sub-codebooks.

If the HARQ-ACK codebook generated by the terminal 202 includes only theHARQ-ACK bits of all the scheduled downlink subframes in the set M ofpreconfigured downlink subframes, that is, the HARQ-ACK bits of all thedownlink subframes in the instantly scheduled downlink subframe set,when generating the HARQ-ACK codebook, the terminal 202 may generate asub-codebook corresponding to each of N instantly scheduled downlinksubframe subsets. Optionally, the terminal 202 may form a HARQ-ACKcodebook by cascading N generated sub-codebooks.

As described above, the terminal 202 and the access network device 201need to know the division rule of the set M of preconfigured downlinksubframes in advance, and the rule is the same for the terminal 202 andthe access network device 201. Herein, when generating the HARQ-ACKcodebook by means of cascading, the terminal 202 also needs to use arule that both the terminal 202 and the access network device 201 knowin advance. For example, during cascading, according to the bit quantityof the HARQ-ACK that needs to be fed back, the terminal 202 places, at afront location, a sub-codebook corresponding to a subset ofpreconfigured downlink subframes with a smaller bit quantity of aHARQ-ACK that needs to be fed back, and places, at a back location, asub-codebook corresponding to a subset of preconfigured downlinksubframes with a larger bit quantity of a HARQ-ACK that needs to be fedback. In this way, the access network device 201 also parses theHARQ-ACK codebook according to a same rule, and therefore a HARQ-ACK bitcan be accurately learned.

7. In Step S305, the Terminal 202 Generates the Uplink ControlInformation by Performing Channel Encoding on the Generated HARQ-ACKCodebook.

The terminal 202 performs channel encoding on the HARQ-ACK codebookafter generating the codebook. In this embodiment of the presentdisclosure, a type of channel encoding is not limited, and the channelencoding may be various channel encoding such as linear block encoding,convolutional coding, or Turbo coding. If the linear block encoding suchas Reed Muller (RM) coding is used, cyclic redundancy check (CRC)usually does not need to be added before encoding. If the convolutionalcoding or the Turbo coding is used, CRC may be added before encoding,and certainly, CRC may be not added before encoding. This is not limitedin this embodiment of the present disclosure.

Optionally, the terminal 202 may use different encoding manners and CRCadding manners according to a codebook size. For example, when thecodebook size is greater than a preset threshold, the convolutionalcoding is used, and in this case, CRC is added; when the codebook sizeis less than or equal to the preset threshold, the RM code is used, andin this case, CRC may be not added.

8. Step S306. The Terminal 202 Sends the Uplink Control Information tothe Access network device 201.

The LTE system is used as an example. The terminal 202 may send, on aPUCCH or a PUSCH, the uplink control information generated in step S305.

After performing the channel encoding and before sending the uplinkcontrol information, the terminal 202 further needs to map encodedHARQ-ACK information to a physical resource. The physical resource maybe a PUCCH resource or a PUSCH resource. Herein, the PUCCH resource isused as an example to describe how the terminal 202 determines thephysical resource.

Optionally, the terminal 202 may determine the PUCCH resource accordingto resource indication information. The terminal 202 obtains a PUCCHresource set, and the PUCCH resource set includes a PUCCH resource of atleast one PUCCH format. The terminal 202 determines the PUCCH resourcefrom the PUCCH resource set according to the resource indicationinformation.

Specifically, the terminal 202 may receive high-layer signaling such asRRC signaling in advance, and obtain the PUCCH resource set configuredby the access network device 201 for the terminal 202, and the setincludes at least two PUCCH resources. The PUCCH resources included inthe set may be in a same format, for example, a PUCCH format (forexample, a format 3) in the LTE system in a current CA mode or a newPUCCH format (for example, a PUCCH format 4 that is based on a PUSCHchannel structure); or at least two PUCCH formats may be included, forexample, the foregoing format 3 and format 4, or at least two newformats.

Then, the terminal 202 determines a first PUCCH resource from the PUCCHresource set according to the resource indication information. Theresource indication information may include a downlink control channelused for currently scheduling a downlink data channel, and mayspecifically include a bit or another implicit status combination on thecontrol channel, such as a newly added bit, or a reused current transmitpower control (TPC) field.

Optionally, different PUCCH formats may be used for different codebooksizes, to carry HARQ-ACKs, for example, the format 4 is used for acodebook size greater than a threshold, and the format 3 is used for acodebook size less than or equal to the threshold. Specifically, acorrespondence may be established between different states of theresource indication information and different PUCCH formats, and thenthe PUCCH format and the PUCCH resource are determined according to theresource indication information. Alternatively, a relationship amongresource indication information, a codebook size, and a PUCCH format isestablished, and then the PUCCH resource and the PUCCH format aredetermined according to the received resource indication information andthe determined codebook size.

9. Step S307. The access network device 201 receives the uplink controlinformation, obtains the HARQ-ACK codebook, and determines the receivingstatus of the downlink data.

After receiving the downlink control information sent by the terminal202, the access network device 201 obtains the HARQ-ACK codebook afterperforming channel decoding in a channel encoding manner the same asthat used by the terminal 202.

If the terminal 202 combines a plurality of sub-codebooks into aHARQ-ACK codebook by means of cascading when generating the HARQ-ACKcodebook, the access network device 201 also parses, in a cascadingmanner the same as that used by the terminal 202, the plurality ofsub-codebooks included in the HARQ-ACK codebook.

Optionally, the access network device 201 determines, according to thepre-learned division rule that is of the set M of preconfigured downlinksubframes and that is the same as that of the terminal 202, the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe in each subset of preconfigured downlink subframes, and parsesthe HARQ-ACK codebook, so that a HARQ-ACK that is fed back by theterminal 202 for each downlink subframe is accurately learned, andfurther, the status of receiving the downlink data in the downlinksubframe by the terminal 202 is determined.

Embodiment 2

For a structure of a wireless communications system provided inEmbodiment 2, refer to FIG. 2B.

In Embodiment 2, a set M of preconfigured downlink subframes is notdivided into subsets, a terminal 202 feeds back a HARQ-ACK only for adownlink subframe scheduled by an access network device 201, and theterminal 202 determines whether downlink scheduling information isundetected, so that the terminal 202 fills in a NACK for a HARQ-ACK atan undetected location, to generate a HARQ-ACK codebook consistent withthat understood by the access network device 201.

A process of downlink scheduling, downlink data transmission, andHARQ-ACK information feedback between the access network device 201 andthe terminal 202 is described below with reference to FIG. 4. Theprocess includes the following steps:

S401. The access network device 201 sends downlink schedulinginformation of a downlink subframe F(i, j) and indication information tothe terminal 202.

S402. The terminal 202 receives the downlink scheduling information andthe indication information.

S403. The access network device 201 sends, in the downlink subframe F(i,j), downlink data scheduled by the downlink scheduling information sentin step S401.

S404. The terminal 202 determines, according to the downlink schedulinginformation and the indication information that are received in stepS402, a downlink subframe scheduled by the access network device 201,for example, the terminal 202 determines, according to the receiveddownlink scheduling information, a downlink subframe scheduled by thereceived downlink scheduling information, and determines, according tothe indication information, a downlink subframe that is scheduled by theaccess network device 201 according to downlink scheduling informationundetected by the terminal 202, so as to determine a downlink subframeactually scheduled by the access network device 201, that is, a downlinksubframe instantly scheduled by the access network device 201; andreceives, in the determined downlink subframe scheduled by the accessnetwork device 201, downlink data scheduled by the downlink schedulinginformation.

S405. The terminal 202 generates a HARQ-ACK codebook according to areceiving status of the downlink data received in the downlink subframeF(i, j) and a bit quantity of a HARQ-ACK that needs to be fed back forthe downlink subframe F(i, j), and generates uplink control informationby encoding the generated HARQ-ACK codebook.

S406. The terminal 202 sends the generated uplink control information tothe access network device 201.

S407. The access network device 201 obtains the HARQ-ACK codebook afterdecoding the received uplink control information, and determines,according to the obtained HARQ-ACK codebook, the receiving status of thedownlink data in the downlink subframe F(i, j) that is scheduled in aset M of preconfigured downlink subframes.

It can be learned after comparing FIG. 4 and FIG. 3 that, in the stepsshown in FIG. 4, in step S401, the access network device 201 sends notonly the downlink scheduling information but also the indicationinformation to the terminal 202, and in step S402, the terminal 202receives not only the downlink scheduling information but also theforegoing indication information sent by the access network device 201.For a specific implementation of the indication information, refer tosubsequent descriptions.

In step S405, the terminal 202 needs to determine, according to thereceived downlink scheduling information and indication information, thedownlink subframe scheduled by the access network device 201, andgenerate, according to the receiving status of the downlink data and thebit quantity of the HARQ-ACK that needs to be fed back for the downlinksubframe, the HARQ-ACK codebook for the downlink subframe scheduled bythe access network device 201.

In step S407, the access network device 201 obtains the HARQ-ACKcodebook after decoding the received uplink control information. In thiscase, the access network device 201 needs to parse the HARQ-ACK codebookaccording to the scheduled downlink subframe instead of the set M ofpreconfigured downlink subframes, to obtain the receiving status of thedownlink data in the scheduled downlink subframe.

Step S401 and step S403 may be completed in a same step. For example,for an LTE system, the access network device 201 sends, in a samedownlink subframe used for sending the downlink scheduling information,the downlink data scheduled by the downlink scheduling information. Inthis case, step S402 and step S404 may also be completed in a same step.The terminal 202 may receive downlink data in a downlink subframeaccording to received downlink scheduling information in the samedownlink subframe.

In addition, to send downlink scheduling information in a downlinksubframe m and schedule the terminal to receive downlink data that is ina downlink subframe m+1, the access network device 201 may use a mannershown in FIG. 4: sending the scheduling information before sending thedownlink data. Accordingly, the terminal 202 receives the downlinkscheduling information first, and then receives the downlink dataaccording to the received downlink scheduling information.Alternatively, a case in which downlink scheduling information is sentin a downlink subframe m on a carrier 1 and the terminal is scheduled toreceive downlink data that is in a downlink subframe m on a carrier 2 isequivalent to that the downlink scheduling information and the downlinkdata scheduled by the downlink scheduling information are sent andreceived in a downlink subframe at a same moment, but the downlinkscheduling information and the downlink data scheduled by the downlinkscheduling information are on different carriers.

In addition, the indication information may be sent together with thedownlink scheduling information, or may be sent separately, for example,be sent by using separate signaling. One downlink subframe F(i, j) maycorrespond to one piece of indication information, or a plurality ofdownlink subframes may correspond to one piece of indicationinformation.

In Embodiment 2, the HARQ-ACK codebook generated by the terminal 202includes only the HARQ-ACK for the downlink subframe scheduled by theaccess network device 201. Therefore, a size of the HARQ-ACK codebook isreduced, and in comparison with feeding back HARQ-ACKs for all downlinksubframes in the set M of preconfigured downlink subframes, occupationof an uplink control channel such as a PUCCH is reduced and datatransmission efficiency is improved. When parsing the HARQ-ACK codebook,the access network device 201 needs to parse only the HARQ-ACK for thescheduled downlink subframe, so that processing load of the accessnetwork device 201 is reduced.

The indication information is described in detail below.

In Embodiment 2, the HARQ-ACK codebook generated by the terminal 202includes only the HARQ-ACK for the downlink subframe F(i, j) scheduledby the access network device 201, that is, the HARQ-ACK codebook isgenerated for the foregoing instantly scheduled downlink subframe set.

As shown in FIG. 5A to FIG. 5D, ten carriers are configured for theterminal 202, and each carrier is a TDD configuration 2. In this case, aset of preconfigured downlink subframes associated with an uplinksubframe 2 on an uplink primary component carrier includes all downlinksubframes 4, 5, 6, and 8 on all the ten carriers.

It is assumed that, in a specific scheduling scenario, an instantlyscheduled downlink subframe set that is actually scheduled for theterminal 202 includes subframes 4 on carriers 1 to 7, subframes 5 on thecarrier 1, the carrier 3, and the carrier 5, subframes 6 on the carriers1 to 6, and subframes 8 on the carriers 1 to 5, and in this case, thesecurrently actually scheduled downlink subframes form the instantlyscheduled downlink subframe set. It can be learned that the instantlyscheduled downlink subframe set is a subset of the foregoing set ofpreconfigured downlink subframes.

In this case, in Embodiment 2, a HARQ-ACK codebook that needs to betransmitted in the uplink subframe 2 on the uplink primary componentcarrier is determined according to the instantly scheduled downlinksubframe set, that is, a HARQ-ACK codebook size in this case is 21. Itis assumed herein that each downlink subframe corresponds to oneHARQ-ACK bit.

The terminal 202 can accurately identify the instantly scheduleddownlink subframe set according to the indication information, so thatthe access network device 201 and the terminal 202 have consistentunderstanding of the HARQ-ACK codebook. Optionally, the foregoingobjective may be implemented by using the indication information. Theindication information may be carried on a downlink control channel, andthe downlink control channel may be the foregoing downlink controlchannel used for scheduling the downlink data channel in the downlinksubframe, that is, a downlink control channel used for sending downlinkscheduling information of the downlink subframe.

Optionally, the indication information may include first indicationinformation and second indication information. The first indicationinformation may be referred to as a “downlink assignment index (DownlinkAssignment Index, DAI) index indicator”, and the second indicationinformation may be referred to as a “DAI end indicator”.

The foregoing two pieces of indication information may be newly addedbits or reused existing bits on the current downlink control channel, ormay be implicit indicators that are not bits, for example, scramblingcode or a combination of some statuses of some bits. Alternatively, theDAI end indicator may be carried on a separate control channel.

In the following, each downlink control channel includes a DAI indexindicator of two bits and a DAI end indicator of two bits as an example,to describe in detail how to determine, by using these two DAI fields,the HARQ-ACK codebook that is determined based on the instantlyscheduled downlink subframe set.

Values of the DAI index indicator on respective downlink controlchannels may be successively accumulated according to a sequence ofcarriers before subframes (certainly, another sequence is not excludedprovided that the sequence is predefined). It should be noted thatbecause currently there is only a DAI index of two bits, cyclic countingis required. For example, an [(X−1) mod 4]+1 rule may be used, that is,X=1, X=5, and X=9 all correspond to a value 1 of the DAI index indicator(which, for example, is represented by a state ‘00’), and X is an actualaccumulated counting value.

In this way, if the terminal 202 does not detect some downlink controlchannels, for example, the terminal 202 successively receives downlinkcontrol channels whose DAI indexes are 1 and 4, the terminal 202 maylearn that two downlink control channels, between the downlink controlchannels whose DAI indexes are 1 and 4, whose DAI indexes arerespectively 2 and 3 are undetected. In this way, when determining theHARQ-ACK codebook, the terminal 202 may put two 0 bits at HARQ-ACK bitlocations associated with downlink subframes corresponding to theforegoing two undetected downlink control channels, that is, fill inNACKs.

However, if only the DAI index indicator is used, although it can befound that a downlink control channel between two received downlinkcontrol channels is undetected, an undetected downlink control channelthat is at the end cannot be found. For example, it is assumed that theaccess network device 201 schedules four downlink control channels intotal, and values of DAI index indicators are successively 1, 2, 3, and4, but the terminal 202 receives only three downlink control channelswhose values of DAI index indicators are 1, 2, and 3. In this case, theterminal 202 cannot find that the last downlink control channel isundetected.

To resolve a problem that the last downlink control channel isundetected, the DAI end indicator may be optionally introduced.Certainly, this method is not a unique method for determining that thelast downlink control channel is undetected. For example, if UE fails todetermine that the last downlink control information is undetected, CRCcheck of the access network device 201 fails, and therefore the accessnetwork device 201 may determine that the HARQ-ACK codebook fed back bythe terminal 202 is incorrect. Once the CRC check of the access networkdevice 201 fails, the access network device 201 considers that eachHARQ-ACK bit in the HARQ-ACK codebook currently fed back by the terminal202 is a NACK, and the access network device 201 subsequently startsphysical layer retransmission scheduling. In addition, the CRC checkensures that the access network device 201 does not incorrectly detect aNACK of the terminal 202 as an ACK, so as to prevent a severe errorevent that a NACK is incorrectly determined as an ACK. The error eventcauses physical layer packet loss, that is, the access network device201 considers that the terminal 202 correctly receives downlink datathat is actually not correctly received, and therefore the accessnetwork device 201 subsequently starts higher layer retransmission suchas Radio Link Control (RLC) layer retransmission instead of physicallayer retransmission. Compared with the physical layer retransmission,the higher layer retransmission greatly reduces resource utilizationefficiency of a system.

It should be noted that, in the foregoing method in which the accessnetwork device 201 determines, with reference to CRC and the DAI indexindicator, that the HARQ-ACK codebook is incorrect, once the accessnetwork device 201 determines that the HARQ-ACK codebook is incorrect,retransmission scheduling of all downlink subframes fed back accordingto the HARQ-ACK codebook needs to be started. Downlink data that is in adownlink subframe and that is correctly received by the terminal 202also needs to be retransmitted. Therefore, data transmission efficiencyis still not high in some sense. Therefore, optionally, the terminal 202may determine, according to a DAI end indicator described below, thatthe last downlink scheduling information is undetected. This methodsignificantly improves data transmission efficiency compared with themethod of using the CRC and the DAI index indicator.

Optional implementations of the DAI end indicator are described below.

Optional Implementation 1

As shown in FIG. 5A, the DAI end indicator is used to indicate a totalquantity of PDSCHs scheduled in a current subframe in the instantlyscheduled downlink subframe set. In a CA mode, the PDSCH scheduled inthe current subframe may include each downlink subframe on aggregatedcarriers that has a same subframe number as the current subframe. Aspecific modulo rule of a value of a total DAI quantity is consistentwith that of the DAI index indicator, that is, [(X−1) mod 4]+1.

Optional Implementation 2

As shown in FIG. 5B, the DAI end indicator is used to indicate a totalquantity of PDSCHs scheduled in a current subframe and previoussubframe(s) in the instantly scheduled downlink subframe set.

In addition, a method of predictive scheduling may be further used. Forexample, denominators in FIG. 5B are changed into 1. In this case, theDAI end indicator is used to indicate a total quantity of PDSCHsscheduled in the instantly scheduled downlink subframe set, but theaccess network device 201 needs to perform prediction during scheduling.For example, at a moment of scheduling a subframe 4, whether subframes5, 6, and 8 need to be scheduled and an accurate quantity of scheduledsubframes need to be predicted because values of a total DAI quantity onthese downlink control channels need to be consistent. Such predictivescheduling causes specific implementation complexity.

For the optional implementations 1 and 2, it should be noted that thesecond indication information may be in each piece of downlinkscheduling information used for scheduling the downlink subframe; or thesecond indication information does not need to be in downlink schedulinginformation used for scheduling the downlink subframe, and it only needsto be ensured that there is at least one piece of second indicationinformation in a plurality of scheduled downlink subframes that have aspecific subframe number, or it only needs to be ensured that there isat least one piece of second indication information in a plurality ofscheduled downlink subframes in an instantly scheduled downlink subframeset.

Optional Implementation 3

As shown in FIG. 5C, the DAI end indicator is used to indicate last XPDSCHs in the instantly scheduled downlink subframe set, for example,X=3. In this case, values of DAI end indicators corresponding to thelast three subframes are reversely set to 4, 3, and 2, and values ofother DAI end indicators are 1.

Optional Implementation 4

As shown in FIG. 5D, the DAI end indicator is used to indicate the lastX PDSCHs scheduled in each subframe in the instantly scheduled downlinksubframe set, for example, X=3. In this case, values of DAI endindicators corresponding to the last three subframes in each subframeare reversely set to 4, 3, and 2, and values of other DAI end indicatorsin the subframe are 1.

In addition, a total quantity indicator of the DAI end indicators mayfurther include a quantity of special downlink control channels, and thespecial downlink control channel is used for instructing to release asemi-persistent scheduling resource and is not used for scheduling aPDSCH. Moreover, an accumulated counting value of the DAI indexindicator may further include the special downlink control channel.

The DAI index indicator and the DAI end indicator are used, so that evenif some downlink control channels are undetected, the terminal 202 canstill accurately restore a HARQ-ACK codebook corresponding to a downlinksubframe actually scheduled by the access network device 201.

However, in the foregoing solutions, it is assumed that each downlinksubframe corresponds to one HARQ-ACK bit. If different data channeltransmission modes are configured for carriers, bit quantities ofHARQ-ACKs corresponding to downlink subframes on different carriers maybe different.

For example, LTE supports nine data channel transmission modes shown inTable 1, and in transmission modes 1, 2, 5, 6, and 7, a PDSCH scheduledin a downlink subframe is a single transport block, that is, eachdownlink subframe corresponds to one HARQ-ACK bit, and in transmissionmodes 3, 4, 8, and 9, a PDSCH scheduled in a downlink subframe may betwo transport blocks, that is, each downlink subframe corresponds to twoHARQ-ACK bits.

As described above, as technologies develop, in the CA mode, differenttransmission modes may be used for carriers configured for the terminal202. The method, provided in Embodiment 2, of generating the HARQ-ACKcodebook based on the instantly scheduled downlink subframe set maycause an error. For example:

As shown in FIG. 6, it is assumed that eight FDD carriers are configuredfor the terminal 202, and one downlink subframe is used as an example.It is assumed that a maximum quantity of transport blocks that can bescheduled in each downlink subframe configured for carriers 1 to 8 aresuccessively {1, 2, 2, 2, 1, 1, 2, 1}, and the access network device 201schedules downlink data channels in the downlink subframe on sixcarriers. According to the method in Embodiment 2, values of DAI indexindicators on corresponding downlink control channels are successively{1, 2, 3, 4, 1, 2}.

It is assumed that the terminal 202 does not detect a downlink controlchannel in the downlink subframe on the carrier 4, and the terminal 202may find, by using values 3 and 1 of two successive DAI indexindicators, that a downlink control channel on which a value of a DAIindex indicator is 4 is undetected, but the terminal 202 does not knowwhether the undetected downlink control channel is a downlink controlchannel on a carrier 4 or a carrier 5. The downlink subframe on thecarrier 4 corresponds to two HARQ-ACK bits, and the downlink subframe onthe carrier 5 corresponds to one HARQ-ACK bit. Therefore, the terminal202 does not know to fill in one or two Os. Consequently the terminal202 and the access network device 201 may have inconsistentunderstanding of the HARQ-ACK codebook, and finally an error is causedwhen the access network device 201 parses the HARQ-ACK codebook.

In Embodiment 2, in the CA mode, different data channel transmissionmodes may be configured for different carriers of the terminal 202, andtherefore maximum quantities of transport blocks scheduled in differentdownlink subframes may be unequal. Consequently, the solution ofdetermining the HARQ-ACK codebook based on the instantly scheduleddownlink subframe set is prone to an error. Therefore, a solution inEmbodiment 3 is provided with reference to Embodiment 1 and Embodiment2.

Embodiment 3

A third wireless communications system is provided in Embodiment 3. Aset M of preconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframes, and a terminal 202 determines aninstantly scheduled downlink subframe subset in each subset ofpreconfigured downlink subframes according to the indication informationprovided in Embodiment 2, and generates a HARQ-ACK codebook for theinstantly scheduled downlink subframe subset.

For a structure of the wireless communications system provided inEmbodiment 3, also refer to FIG. 2A. For a process of downlinkscheduling, downlink data transmission, and HARQ-ACK informationfeedback between an access network device 201 and the terminal 202,refer to FIG. 4.

In Embodiment 3, the access network device 201 sends not only downlinkscheduling information but also the indication information described inEmbodiment 2 to the terminal 202. In Embodiment 3, the terminal 202feeds back a HARQ-ACK only for a downlink subframe scheduled by theaccess network device 201.

A difference between Embodiment 3 and Embodiment 2 lies in that, inEmbodiment 3, the set M of preconfigured downlink subframes is dividedinto N subsets of preconfigured downlink subframes, N is an integergreater than or equal to 2, a bit quantity of a HARQ-ACK that needs tobe fed back for each downlink subframe in one subset of preconfigureddownlink subframes is a predetermined value, and bit quantities ofHARQ-ACKs that need to be fed back for any downlink subframes indifferent subsets of preconfigured downlink subframes are different.

In Embodiment 3, first indication information, that is, a DAI indexindicator is for a subset of preconfigured downlink subframes, and firstindication information corresponding to a downlink subframe F(i, j) inthe subset of preconfigured downlink subframes is used to indicate asequence number, according to a setting sequence, of the downlinksubframe F(i, j) in scheduled downlink subframes in the subset ofpreconfigured downlink subframes including the downlink subframe F(i,j). For example, accumulative counting may be performed on the firstindication information in the scheduled downlink subframe in the subsetof preconfigured downlink subframes.

Accordingly, when the terminal 202 generates the HARQ-ACK codebook, thegenerated HARQ-ACK codebook includes at least one sub-codebook, the atleast one sub-codebook is in one-to-one correspondence with at least onesubset of preconfigured downlink subframes, the at least one subset ofpreconfigured downlink subframes is at least one of the N subsets ofpreconfigured downlink subframes, and the at least one subset ofpreconfigured downlink subframes is a subset including downlinksubframes in which the downlink scheduling information is received bythe terminal 202.

The at least one sub-codebook is generated in the following manner:

The terminal 202 generates, for one of the at least one subset ofpreconfigured downlink subframes according to the sequence numberindicated by the first indication information and according to areceiving status of downlink data received in the downlink subframe F(i,j) and a bit quantity of a HARQ-ACK that needs to be fed back for thedownlink subframe F(i, j), a sub-codebook corresponding to the onesubset of preconfigured downlink subframes.

In Embodiment 3, in addition to the first indication information,indication information further includes second indication information,that is, a DAI end indicator.

The second indication information corresponds to one subset ofpreconfigured downlink subframes, and the second indication informationcorresponding to one subset of preconfigured downlink subframes has aplurality of optional implementations. For example:

Optional Implementation 1

The second indication information is used to indicate a total quantityof scheduled downlink subframes that are in the subset of preconfigureddownlink subframes including the downlink subframe F(i, j) and whosesubframe numbers are j.

Optional Implementation 2

The second indication information is used to indicate a total quantityof a scheduled downlink subframe whose subframe number is j and adownlink subframe before the downlink subframe whose subframe number isj, where the scheduled downlink subframe whose subframe number is j andthe downlink subframe before the downlink subframe whose subframe numberis j are in the subset of preconfigured downlink subframes including thedownlink subframe F(i, j).

Optional Implementation 3

The second indication information is used to indicate a total quantityof scheduled downlink subframes in the subset of preconfigured downlinksubframes including the downlink subframe F(i, j).

Optional Implementation 4

The second indication information is used to indicate a total quantityof transport blocks transmitted in a scheduled downlink subframe that isin the subset of preconfigured downlink subframes including the downlinksubframe F(i, j) and whose subframe number is J.

Optional Implementation 5

The second indication information is used to indicate a total quantityof transport blocks transmitted in a scheduled downlink subframe whosesubframe number is j and a downlink subframe before the downlinksubframe whose subframe number is j, where the scheduled downlinksubframe whose subframe number is j and the downlink subframe before thedownlink subframe whose subframe number is j are in the subset ofpreconfigured downlink subframes including the downlink subframe F(i,j).

Optional Implementation 6

The second indication information is used to indicate a total quantityof transport blocks transmitted in a scheduled downlink subframe in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j).

Optional Implementation 7

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), A_(X−2), . . . , A₁, and A₀,values of the second indication information corresponding to otherdownlink subframes are respectively A₀, the other downlink subframes aredownlink subframes, other than the last one, last but one, . . . , lastbut X−2, and last but X−1 of the sorted scheduled downlink subframes, inthe subset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.X is a positive integer greater than 1.

Optional Implementation 8

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to scheduled downlink subframes, sorted according to areversed sequence of the setting sequence, in the subset ofpreconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}. X is a positive integer greater than 1.

Optional Implementation 9

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes that are sorted accordingto the setting sequence and whose subframe numbers are j arerespectively A_(X−1), A_(X−2), A₁, and A₀, values of the secondindication information corresponding to other downlink subframes whosesequence numbers are j are respectively A₀, the other downlink subframeswhose sequence numbers are j are downlink subframes, other than the lastone, last but one, . . . , last but X−2, and last but X−1 of the sortedscheduled downlink subframes whose subframe numbers are j, in the subsetof preconfigured downlink subframes including the downlink subframe F(i,j), and A_(X−1), A_(X−2), . . . , A₁, and A₀ are different values. X isa positive integer greater than 1.

Optional Implementation 10

Values of the second indication information corresponding to scheduleddownlink subframes that are sorted according to a reversed sequence ofthe setting sequence in the subset of preconfigured downlink subframesand whose subframe numbers are j are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}.

Optional Implementation 11

The second indication information is used to indicate a bit quantity ofa sub-codebook corresponding to the subset of preconfigured downlinksubframes including the downlink subframe F(i, j), and the bit quantitymay also be referred to as a codebook size. The codebook size is lessthan a bit quantity of a HARQ-ACK corresponding to the subset ofpreconfigured downlink subframes but is greater than or equal to aquantity of downlink subframes in the instantly scheduled downlinksubframe subset or a quantity of transport blocks. When the codebooksize is greater than the quantity of downlink subframes in the instantlyscheduled downlink subframe subset or the quantity of transport blocks,both UE and a base station determine that at least one NACK is filled inat the end of the codebook, and a specific quantity of filled-in NACKsis the codebook size minus a quantity of downlink subframes that are inthe instantly scheduled downlink subframe subset and in which downlinkdata is actually scheduled or the quantity of transport blocks. Forexample, ten carriers are configured for the UE, each carrier is a TDDuplink-downlink configuration 2, subframes 4, 5, 6, and 8 that are onthe ten carriers and that are corresponding to an uplink subframe 2 areused as examples, and for each of N groups, when the base stationschedules downlink data for the UE in the subframe 4, it ispre-estimated that a quantity of downlink subframes that are in theinstantly scheduled downlink subframe subset and in which downlink dataof the UE is actually scheduled is X. X meets the following formula:[(X−1) mod 4]+1=2. Then the base station performs scheduling for the UEin the subframes 5, 6, and 8, but finally, due to a specific reason, aquantity of downlink subframes that are in the instantly scheduleddownlink subframe subset and in which the base station actuallyschedules the downlink data of the UE is 20. The reason includes acontrol channel capacity, or that another UE has a higher priority thanthe UE or scheduling on an unauthorized carrier further needs to dependon a load status on the carrier, or the like. The quantity of finallyactually scheduled downlink subframes is 20, and a pre-estimated actualvalue of X may be finally determined as 22. Therefore, according to thisrule, both the UE and the base station construe a codebook size of aHARQ-ACK codebook in this case as 22 bits, locations of the first 20bits of the 22 bits correspond to downlink subframes in the instantlyscheduled downlink subframe subset that are actually scheduled, andNACKs are filled in at locations of the last two bits. Alternatively, ifthe base station finally determines that a quantity of downlinksubframes that are in the instantly scheduled downlink subframe subsetand in which the UE is actually scheduled is 16, X may be understood as18, and NACKs are filled in at locations of the last two bits of theHARQ-ACK codebook. In this embodiment, the base station may pre-estimatea codebook size of one HARQ-ACK codebook, and after actually schedulingthe UE in an instantly scheduled downlink subframe subset, finallydetermine a location of a HARQ-ACK bit corresponding to downlink dataactually scheduled in the HARQ-ACK codebook, and fill in a NACK atanother location. Therefore, a predictive scheduling problem is avoided,and the foregoing flexible X parsing does not limit a quantity ofscheduled subframes. Alternatively, N numbers of actually scheduleddownlink subframes may be configured for the UE, where N is greater than1, and then a total DAI quantity is used for instructing to dynamicallyselect one of the N numbers as a current HARQ-ACK codebook size. In thissolution, predictive scheduling may be not required either, that is, aNACK is filled in for the dynamically selected codebook size, but thissolution is not as flexible as the method in the foregoing embodimentbecause once the dynamically selected codebook size is determined, anactually scheduled downlink subframe in a current instantly scheduleddownlink subframe subset cannot be determined at random.

In this case, when generating a sub-codebook corresponding to the subsetof preconfigured downlink subframes, the terminal 202 may generate,according to the second indication information and the sequence numberthat is indicated by the first indication information and according tothe receiving status of the downlink data received in the downlinksubframe F(i, j) and the bit quantity of the HARQ-ACK that needs to befed back for the downlink subframe F(i, j), a sub-codebook correspondingto a subset of preconfigured downlink subframes.

In the foregoing descriptions of the first indication information andthe second indication information, the involved setting sequence mayinclude a sequence between a carrier and a subframe, a carrier sequence,and a subframe sequence.

The sequence between a carrier and a subframe may include: carriersbefore subframes, or subframes before carriers.

The carrier sequence may include: ascending order of carrier indexes, ordescending order of carrier indexes. The subframe sequence includes:ascending order of subframe moments, or descending order of subframemoments.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, bit quantities of HARQ-ACKs thatneed to be fed back for downlink subframes in different subsets ofpreconfigured downlink subframes are different, and bit quantities ofHARQ-ACKs that need to be fed back in downlink subframes in a samesubset of preconfigured downlink subframes are the same. The firstindication information and the second indication information arecorresponding to a subset of preconfigured downlink subframes instead ofthe set M of preconfigured downlink subframes. In this way, the terminal202 can accurately determine, according to the first indicationinformation, optionally, also according to the second indicationinformation, a subset of preconfigured downlink subframes in whichdownlink scheduling information is undetected, and the terminal 202 alsolearns, in advance, a bit quantity of a HARQ-ACK that needs to be fedback in one subset of preconfigured downlink subframes. In this way,when it is determined that the downlink scheduling information isundetected, a correct quantity of HARQ-ACKs can be filled in.

In the following, refer to example descriptions in FIG. 7A and FIG. 7B.Ten carriers of the terminal 202 are classified into two groupsaccording to data channel transmission modes. Carriers {1, 4, 5, 7, 10}are a first group, 20 downlink subframes, that is, downlink subframes 4,5, 6, and 8 on the first group of carriers form a first subset ofpreconfigured downlink subframes, and a PDSCH that is scheduled in eachsubframe in a current data channel transmission mode corresponds to onetransport block, that is, corresponds to one HARQ-ACK bit. Carriers {2,3, 6, 8, 9} are a second group, 20 downlink subframes, that is, downlinksubframes 4, 5, 6, and 8 on the second group of carriers form a secondsubset of preconfigured downlink subframes, and a PDSCH that isscheduled in each subframe in the current data channel transmission modecorresponds to two transport blocks, that is, corresponds to twoHARQ-ACK bits.

For the first subset of preconfigured downlink subframes, actuallyscheduled downlink subframes are subframes 4 and subframes 6 on all thefirst group of carriers, subframes 5 on the carriers 1, 4, 5, and 10,and subframes 8 on the carriers 1 and 4. These subframes form a firstinstantly scheduled downlink subframe subset.

HARQ-ACKs in a first sub-codebook corresponding to the first instantlyscheduled downlink subframe subset are sorted according to a settingsequence, and optionally, this may be specifically identified by thefirst indication information, that is, a DAI index indicator accordingto a positive sequence of carriers before subframes. The DAI indexindicator may be on each downlink control channel used for schedulingthe first instantly scheduled downlink subframe subset. If there is thespecial downlink control channel, the DAI index indicator may further beon the special downlink control channel. Alternatively, if there is onlythe special downlink control channel, the DAI index indicator is only onthe special downlink control channel. A value of the DAI index indicatormay be accumulatively counted according to the positive sequence ofcarriers before subframes. The positive sequence herein may bespecifically ascending order or descending order of carrier indexes(index) that may also be referred to as carrier sequence numbers, andthen ascending order of subframe moments. Another carrier arrangementmanner is not excluded provided that a sequence is predefined.

Herein, the DAI index indicator may occupy two bits that represent fourstates {00, 01, 10, 11}. If the DAI index indicator is accumulativelycounted according to the setting sequence in the downlink subframesscheduled in the subset of preconfigured downlink subframes, accumulatedcounting values may be respectively {1, 2, 3, 4}. If a value exceeds 4,cyclic counting may be performed, that is, {1, 2, 3, 4, 5(1), 6(2),7(3), . . . }. Specifically, a formula Y=[(X−1) mod 4]+1 may be used forrepresentation. X is a counting value in actual accumulative counting,for example, 1 to 7. Y is a value obtained after cyclic modulo, that is,corresponds to {1, 2, 3, 4, 1, 2, 3}. Certainly, another counting manneris not excluded, for example, {0, 1, 2, 3, 0, 1, 2, 3, . . . }. The DAIindex indicator of two bits is also a specific example, and a solutionof a DAI index indicator of another bit quantity is similar and is notexcluded.

As described above, the terminal 202 can determine an undetecteddownlink control channel between two downlink control channels based onthe DAI index indicator, but cannot determine an undetected downlinkcontrol channel that is at the end. In this case, CRC used beforechannel encoding may be used. For example, if the UE fails to determinethat the downlink control channel that is at the end is undetected, CRCcheck of the access network device 201 fails. Therefore, the accessnetwork device 201 may determine that the HARQ-ACK codebook fed back bythe terminal 202 is incorrect, so that physical layer retransmission isperformed.

Optionally, the access network device 201 may send the second indicationinformation in addition to the first indication information, so that theterminal can determine whether the last one to several downlink controlchannels in the instantly scheduled downlink subframe subset areundetected, or determine a status of the last one to several downlinkcontrol channels in each subframe.

Herein, a DAI end indicator of two bits is used as an example. Herein,it is assumed that the DAI end indicator is on each downlink controlchannel used for scheduling the instantly scheduled downlink subframesubset, and may certainly be on only some of downlink control channelsused for scheduling downlink data channels. In addition, the DAI endindicator may further be on another special downlink control channelthat is not used for scheduling these downlink data channels, forexample, at least one such special downlink control channel is sent ineach subframe or at least one such special downlink control channel issent in each instantly scheduled downlink subframe subset. Theseextended embodiments are not excluded.

As described above, the DAI end indicator may be set by using aplurality of methods. The DAI end indicator may be independently set ineach downlink subframe, or a plurality of downlink subframes correspondto a same DAI end indicator.

For example, for the optional implementation 1 in Embodiment 3, the DAIend indicator may be independently set in each downlink subframe, toindicate a quantity of PDSCHs scheduled in the current subframe.

For the optional implementation 4 in Embodiment 3, the DAI end indicatormay be independently set in each subframe, to indicate a quantity oftransport blocks (Transport Block, TB) scheduled in the currentsubframe.

As shown in FIG. 7A, a DAI end indicator is independently set in eachsubframe in the first instantly scheduled downlink subframe subset, anda value of the DAI end indicator represents a total quantity of downlinkdata channels scheduled in the current subframe. The total quantity mayinclude or may not include a downlink data channel used for SPS becausethe downlink data channel used for SPS is not instantly scheduled, but aperiod and a specific subframe location are pre-determined. Therefore,whether the downlink data channel used for SPS is counted in theforegoing DAI total quantity indicator or not is feasible provided thata rule is defined. In addition, if the special downlink control channelis taken into consideration. The value of the DAI total quantityindicator also needs to include the special downlink control channel,that is, a total quantity of downlink data channels in the currentsubframe and a total quantity of special downlink control channels needto be taken into consideration.

The value of the DAI end indicator may also be specifically set in acyclic modulo manner. A DAI total quantity indicator of two bits is usedas an example (a similar method is used for setting a DAI total quantityindicator of another bit quantity). A formula Y=[(X−1) mod 4]+1 may beused. X is an actual value of a total quantity, for example, a totalquantity of subframes 4 is 7; Y is a value obtained after cyclic modulo,for example, a value of the total quantity of subframes 4 is set to 1.

In this method, the access network device 201 does not need to performprediction in advance during scheduling, so that scheduling complexityis reduced. For example, when the access network device 201 schedulesdata in a subframe n, only a total quantity of downlink data channelsscheduled in the current subframe n needs to be considered for aspecified DAI total quantity indicator, and a quantity of subframes usedfor data scheduling in a subframe n+1 and specific subframe locations donot need to be predicted during scheduling in the subframe n. Inaddition, counting values of previous subframes may be furtheraccumulated in each subframe, and this is specifically shown in a methodin FIG. 5B.

For another example, for the optional implementation 7, the DAI endindicator may be independently set in each subframe, and indicates thelast X−1 PDSCHs scheduled in the current subframe.

As shown in FIG. 7B, in the first instantly scheduled downlink subframesubset, values of the second indication information corresponding to thelast one, last but one, . . . , last but X−2, and last but X−1 ofdownlink subframes scheduled by the setting sequence are respectivelyA_(X−1), A_(X−2), A₁, and A₀, values of the second indicationinformation corresponding to other downlink subframes are respectivelyA₀, the other downlink subframes are downlink subframes, other than thelast one, last but one, . . . , last but X−2, and last but X−1 of thesorted scheduled downlink subframes, in the subset of preconfigureddownlink subframes including the downlink subframe F(i, j), and A_(X−1),A_(X−2), A₁, and A₀ are different values. X is a positive integergreater than 1. Optionally, X is a Y^(th) power of 2, and Y is a bitquantity of the DAI end indicator.

A subframe 4 is used as an example, and a DAI end indicator has twobits, that is, X=4. Values of DAI end indicators corresponding to thelast one, last but one, and last but two subframes are respectivelyA3=4, A2=3, and A1=2, and values of DAI end indicators corresponding tothe other two subframes are both A0=1.

For another example, if only two subframes are scheduled in a subframe8, values of DAI end indicators corresponding to the last one and lastbut one subframes are respectively A3=4 and A2=3. Optionally, the DAIend indicator may be used to indicate scheduling of the last X−1 PDSCHsin the first instantly scheduled downlink subframe subset, and a methodfor determining a value of the DAI end indicator is similar to theforegoing method.

After the first sub-codebook and the second sub-codebook arerespectively determined according to the foregoing rules for setting theDAI index indicator and the DAI end indicator, the terminal 202 cascadesthe two sub-codebooks, for example, arranges the first sub-codebookbefore the second sub-codebook, or arranges the second sub-codebookbefore the first sub-codebook, to form the final HARQ-ACK codebook.

For another example, for the optional implementation 8, DAI endindicators are set to 4, 3, 2, 1, 4, 3, 2, 1, . . . according to areverse sequence of the setting sequence.

It should be noted that, in the foregoing sub-codebook cascadingsolution of forming the final HARQ-ACK codebook by using the pluralityof sub-codebooks, a more robust effect is achieved, where the effect isthat the terminal 202 and the access network device 201 have consistentunderstanding of the final codebook. Specific descriptions are asfollows:

As shown in FIG. 8, CA of twelve FDD carriers is used as an example. Itis assumed that each downlink subframe on carriers 1, 3, 5, 7, 9, and 11corresponds to one HARQ-ACK bit, and each downlink subframe on carriers2, 4, 6, 8, 10, and 12 corresponds to two HARQ-ACK bits. Therefore,based on the foregoing method, six downlink subframes on the carriers 1,3, 5, 7, 9, and 11 form the foregoing first set of preconfigureddownlink subframes, and six downlink subframes on the carriers 2, 4, 6,8, 10, and 12 form the foregoing second set of preconfigured downlinksubframes.

It is further assumed that the first instantly scheduled downlinksubframe subset in which the access network device 201 actuallyschedules the terminal 202 includes downlink subframes 1, 5, 7, and 9 inthe first set of preconfigured downlink subframes, and the secondinstantly scheduled downlink subframe subset includes downlink subframes2, 4, 6, and 8 in the second set of preconfigured downlink subframes.Therefore, values of the first indication information are respectively1, 2, 3, and 4 for the downlink subframes 1, 5, 7, and 9 in the firstsubset of preconfigured downlink subframes, and are respectively 1, 2,3, and 4 for the downlink subframes 2, 4, 6, and 8 in the second subsetof preconfigured downlink subframes.

It is further assumed that the terminal 202 does not detect downlinkscheduling information in the downlink subframe 5 in the first instantlyscheduled downlink subframe subset.

Based on the foregoing assumptions, if the final HARQ-ACK codebook isnot formed in the sub-codebook cascading manner, but sub-codebooks arecombined in ascending order of carrier indexes or the like, there maystill be relatively low probability that the terminal 202 and the accessnetwork device 201 have inconsistent understanding of a HARQ-ACK bitsequence in the final codebook. Certainly, such low probability ofinconsistent understanding may be resolved by means of higher layerretransmission.

For the foregoing assumptions, the terminal 202 may determine that onepiece of downlink scheduling information at a location between locationsat which values of first indication information are 1 and 3 in the firstinstantly scheduled downlink subframe subset is undetected, but theterminal 202 cannot determine whether the undetected downlink schedulinginformation is corresponding to the carrier 3 or the carrier 5.Therefore, when the terminal 202 combines sub-codebooks in ascendingorder of carrier index numbers, there are two possibilities. A firstpossibility is that a corresponding HARQ-ACK bit sequence in a codebookobtained after the combination is corresponding to {1, 22, 3, 44, 66, 7,88, 9}, and a second possibility is that downlink subframescorresponding to a corresponding HARQ-ACK bit sequence in a codebookobtained after the combination are {1, 22, 44, 5, 66, 7, 88, 9}. 1represents one HARQ-ACK bit of the carrier 1, 22 represents two HARQ-ACKbits on the carrier 2, and so on.

Therefore, the access network device 201 and the terminal 202 may haveinconsistent understanding of the final codebook, but for the foregoingsituation, the access network device 201 may also learn, in advance, anundetected subframe that the terminal 202 may be uncertain of, so thatthe access network device 201 can at least accurately obtain a HARQ-ACKbit at another location in the HARQ-ACK codebook, and physical layerretransmission is not started in downlink subframes corresponding to allHARQ-ACK bits in the HARQ-ACK codebook. Alternatively, the accessnetwork device 201 may choose to avoid such a scheduling manner, forexample, the access network device 201 performs continuous downlinksubframe scheduling according to the setting sequence as far aspossible.

However, if the manner of directly cascading the sub-codebooks based onthe groups is used, a problem that the terminal 202 and the accessnetwork device 201 have inconsistent understanding of the final HARQ-ACKcodebook can be resolved. Specifically, the foregoing assumptions arestill used as examples. A cascading manner of arranging a sub-codebookin which each subframe corresponds to one HARQ-ACK bit before asub-codebook in which each subframe corresponds to two HARQ-ACK bits isused, and a final HARQ-ACK codebook obtained after cascading is {1, X,7, 9, 22, 44, 66, 88}, where X is 3 or 5. The access network device 201knows that the access network device 201 actually schedules the terminal202 in which one of a subframe 3 or a subframe 5, and therefore, even ifthe terminal 202 cannot determine whether the HARQ-ACK codebook iscorresponding to the subframe 3 or the subframe 5, the access networkdevice 201 can determine whether the HARQ-ACK codebook is correspondingto the subframe 3 or the subframe 5.

It should be noted that TDD LTE is used as an example for descriptionabove, but this embodiment of the present disclosure is also applicableto another wireless communications system such as FDD LTE. For FDD LTE,in a set M of preconfigured downlink subframes associated with an uplinksubframe, there is only one downlink subframe on a downlink carrier.Therefore, an implementation solution of the FDD LTE system in thisembodiment of the present disclosure may be considered as a special caseof an implementation solution of the TDD LTE system.

In addition, this embodiment of the present disclosure is alsoapplicable to the foregoing CA mode of FDD+TDD CA. In this CA mode, in aset M of preconfigured downlink subframes associated with an uplinksubframe, there is only one downlink subframe on an FDD carrier, andthere may be a plurality of downlink subframes on a TDD carrieraccording to the foregoing HARQ-ACK time sequence.

Embodiment 4

FIG. 9 is a schematic structural diagram of a terminal according toEmbodiment 4 of the present disclosure. As shown in FIG. 9, the terminalincludes a receiving module 901, a processing module 902, and a sendingmodule 903.

The receiving module 901 is configured to receive downlink schedulinginformation of a downlink subframe F(i, j), and the downlink subframeF(i, j) is a subframe in a set M of preconfigured downlink subframescorresponding to an uplink subframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a hybrid automatic repeatrequest-acknowledgement HARQ-ACK that needs to be fed back for eachdownlink subframe in one subset of preconfigured downlink subframes is apredetermined value, and bit quantities of HARQ-ACKs that need to be fedback for any downlink subframes in different subsets of preconfigureddownlink subframes are different.

The receiving module 901 is further configured to receive, in thedownlink subframe F(i, j), downlink data scheduled by the downlinkscheduling information.

The processing module 902 is configured to: generate a HARQ-ACK codebookaccording to a receiving status of the downlink data received by thereceiving module 901 in the downlink subframe F(i, j) and a bit quantityof a HARQ-ACK that needs to be fed back for the downlink subframe F(i,j), where the HARQ-ACK codebook includes at least one sub-codebook, theat least one sub-codebook is in one-to-one correspondence with at leastone subset of preconfigured downlink subframes, the at least one subsetof preconfigured downlink subframes is at least one of the N subsets ofpreconfigured downlink subframes, and the at least one subset ofpreconfigured downlink subframes is a subset including the downlinksubframe in which the terminal receives the downlink data scheduled bythe downlink scheduling information; and generate uplink controlinformation by encoding the HARQ-ACK codebook.

The sending module 903 is configured to send the uplink controlinformation in the uplink subframe.

Optionally, a HARQ-ACK included in the sub-codebook is a HARQ-ACK for ascheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, but does not include aHARQ-ACK for an unscheduled downlink subframe in the subset ofpreconfigured downlink subframes corresponding to the sub-codebook.

Optionally, a HARQ-ACK included in the sub-codebook includes a HARQ-ACKfor a scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook; or a HARQ-ACK included inthe sub-codebook includes at least one filled-in bit and a HARQ-ACK fora scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, and the filled-in bit maybe a preset value such as a NACK. It should be noted that regardless ofwhether the filled-in NACK is included, a bit quantity of thesub-codebook needs to be less than a bit quantity of a HARQ-ACKcorresponding to a subset of preconfigured downlink subframes to whichan instantly scheduled downlink subframe subset belongs. The filled-inbit may be located after a bit location of a HARQ-ACK corresponding to adownlink subframe in the instantly scheduled downlink subframe subset.

Optionally, the receiving module 901 is further configured to: beforethe processing module 902 generates the HARQ-ACK codebook, receive firstindication information corresponding to a downlink subframe F(i, j)included in each of the at least one subset of preconfigured downlinksubframes. The first indication information is used to indicate asequence number, according to a setting sequence, of the downlinksubframe F(i, j) in scheduled downlink subframes in the subset ofpreconfigured downlink subframes including the downlink subframe F(i,j).

The processing module 902 is specifically configured to generate the atleast one sub-codebook in the following manner:

generating, for one of the at least one subset of preconfigured downlinksubframes according to the sequence number indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, the receiving module 901 is further configured to: beforethe processing module 902 generates the HARQ-ACK codebook, receivesecond indication information corresponding to each of the at least onesubset of preconfigured downlink subframes. For content that the secondindication information is used to indicate, refer to descriptions in theforegoing embodiments.

Optionally, the second indication information is used to indicate a bitquantity of a sub-codebook corresponding to the subset of preconfigureddownlink subframes including the downlink subframe F(i, j), and the bitquantity may also be referred to as a codebook size. The codebook sizeis less than a bit quantity of a HARQ-ACK corresponding to the subset ofpreconfigured downlink subframes but is greater than or equal to aquantity of downlink subframes in the instantly scheduled downlinksubframe subset or a quantity of transport blocks. When the codebooksize is greater than the quantity of downlink subframes in the instantlyscheduled downlink subframe subset or the quantity of transport blocks,both UE and a base station determine that at least one NACK is filled inat the end of the codebook, and a specific quantity of filled-in NACKsis the codebook size minus a quantity of downlink subframes that are inthe instantly scheduled downlink subframe subset and in which downlinkdata is actually scheduled or the quantity of transport blocks. Forspecific descriptions of this embodiment, refer to Embodiment 3. Detailsare not described herein again.

The processing module 902 is specifically configured to:

generate, for one of the at least one subset of preconfigured downlinksubframes according to the second indication information and thesequence number that is indicated by the first indication informationand according to the receiving status of the downlink data received inthe downlink subframe F(i, j) and the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe F(i, j), a sub-codebookcorresponding to the one subset of preconfigured downlink subframes.

Optionally, the receiving module 901 is further configured to: beforethe processing module 902 generates the HARQ-ACK codebook, receivesecond indication information corresponding to a downlink subframe F(i,j) included in each of the at least one subset of preconfigured downlinksubframes.

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), A_(X−2), A₁, and A₀, valuesof the second indication information corresponding to other downlinksubframes are respectively A₀, the other downlink subframes are downlinksubframes, other than the last one, last but one, . . . , last but X−2,and last but X−1 of the sorted scheduled downlink subframes, in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to scheduled downlink subframes, sortedaccording to a reversed sequence of the setting sequence, in the subsetof preconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), . . . , A₁, A₀}.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to the last one, last but one, . . . , lastbut X−2, and last but X−1 of scheduled downlink subframes that aresorted according to the setting sequence and whose subframe numbers arej are respectively A_(X−1), A_(X−2), A₁, and A₀, values of the secondindication information corresponding to other downlink subframes whosesequence numbers are j are respectively A₀, the other downlink subframeswhose sequence numbers are j are downlink subframes, other than the lastone, last but one, . . . , last but X−2, and last but X−1 of the sortedscheduled downlink subframes whose subframe numbers are j, in the subsetof preconfigured downlink subframes including the downlink subframe F(i,j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, values of the second indication information correspondingto scheduled downlink subframes that are sorted according to a reversedsequence of the setting sequence in the subset of preconfigured downlinksubframes and whose subframe numbers are j are respectively cyclicvalues of {A_(X−1), A_(X−2), A₁, A₀}.

X is a positive integer greater than 1.

The processing module 902 is specifically configured to:

generate, for one of the at least one subset of preconfigured downlinksubframes according to the second indication information and thesequence number that is indicated by the first indication informationand according to the receiving status of the downlink data received inthe downlink subframe F(i, j) and the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe F(i, j), a sub-codebookcorresponding to the one subset of preconfigured downlink subframes.

Optionally, for the setting sequence, refer to the foregoingdescriptions.

Optionally, the at least one sub-codebook is cascaded in the HARQ-ACKcodebook.

For an optional implementation solution of division of the set M ofpreconfigured downlink subframes, refer to related descriptions inEmbodiment 1.

For an optional implementation in which the processing module 902generates sub-codebooks, forms the HARQ-ACK codebook by using thegenerated sub-codebooks, and generates the uplink control information byperforming channel encoding, and the sending module 903 sends the uplinkcontrol information, refer to processing performed by the terminal 202in Embodiment 1 to Embodiment 3.

For an optional implementation in which the receiving module 901receives the first indication information and the second indicationinformation and the processing module 902 determines, according to thefirst indication information and the second indication information, adownlink subframe scheduled by an access network device, refer toprocessing performed by the terminal 202 in Embodiment 1 to Embodiment3.

For another optional implementation of the terminal provided inEmbodiment 4, refer to the foregoing terminal 202. A repeated part isnot described herein.

Specifically, the processing module 902 is configured to perform aprocessing operation performed by the terminal 202, the receiving module901 may be configured to perform a receiving operation performed by theterminal 202, and the sending module 903 may be configured to perform asending operation performed by the terminal 202.

FIG. 10 shows an optional implementation of the terminal. The processingmodule 902 may be implemented by a processor 1002 in FIG. 10, thereceiving module 901 may be implemented by a receiver 1001 in FIG. 10,and the sending module 903 may be implemented by a transmitter 1003 inFIG. 10. A bus architecture may include any quantity of interconnectedbuses and bridges, and specifically link various circuits of one or moreprocessors represented by the processor 1002 and one or more memoriesrepresented by a memory 1004. The bus architecture may further linkvarious other circuits such as a peripheral device, a voltage regulator,and a power management circuit, which is well known in the art, andtherefore no further description is provided in this specification. Abus interface provides an interface. The receiver 1001 and thetransmitter 1003 may be implemented by a transceiver that provides unitsfor communicating with various other apparatuses on a transmissionmedium. For different terminals, a user interface 1005 may further be aninterface that can be externally or internally connected to a device,and the connected device includes but is not limited to a keypad, adisplay, a loudspeaker, a microphone, a joystick, or the like.

FIG. 11 shows another optional implementation of the terminal. Theprocessing module 902 may be implemented by a processor 1102 in FIG. 11,the receiving module 901 may be implemented by a receiver 1101 in FIG.11, and the sending module 903 may be implemented by a transmitter 1103in FIG. 11.

Embodiment 5

FIG. 12 is a schematic structural diagram of an access network deviceaccording to Embodiment 5 of the present disclosure. As shown in FIG.12, the access network device includes a sending module 1203, areceiving module 1201, and a processing module 1202.

The sending module 1203 is configured to: send downlink schedulinginformation of a downlink subframe F(i, j) to a terminal, and send, tothe terminal in the downlink subframe F(i, j), downlink data scheduledby the downlink scheduling information. The downlink subframe F(i, j) isa subframe in a set M of preconfigured downlink subframes correspondingto an uplink subframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a HARQ-ACK that needs to be fed back foreach downlink subframe in one subset of preconfigured downlink subframesis a predetermined value, and bit quantities of hybrid automatic repeatrequest-acknowledgements HARQ-ACKs that need to be fed back for anydownlink subframes in different subsets of preconfigured downlinksubframes are different.

The receiving module 1201 is configured to receive uplink controlinformation that is sent by the terminal in the uplink subframe and thatis used for feeding back a receiving status of the downlink datascheduled by the downlink scheduling information.

The processing module 1202 is configured to obtain a HARQ-ACK codebookby decoding the uplink control information. The obtained HARQ-ACKcodebook includes at least one sub-codebook, the at least onesub-codebook is in one-to-one correspondence with at least one subset ofpreconfigured downlink subframes, the at least one subset ofpreconfigured downlink subframes is at least one of the N subsets ofpreconfigured downlink subframes, and the at least one subset ofpreconfigured downlink subframes is a subset including downlinksubframes on which the downlink data is scheduled by the downlinkscheduling information.

Optionally, a HARQ-ACK included in the sub-codebook is a HARQ-ACK for ascheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, but does not include aHARQ-ACK for an unscheduled downlink subframe in the subset ofpreconfigured downlink subframes corresponding to the sub-codebook.

Optionally, a HARQ-ACK included in the sub-codebook includes a HARQ-ACKfor a scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook; or a HARQ-ACK included inthe sub-codebook includes at least one filled-in bit and a HARQ-ACK fora scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, and the filled-in bit maybe a preset value such as a NACK. It should be noted that regardless ofwhether the filled-in NACK is included, a bit quantity of thesub-codebook needs to be less than a bit quantity of a HARQ-ACKcorresponding to a subset of preconfigured downlink subframes to whichan instantly scheduled downlink subframe subset belongs. The filled-inbit may be located after a bit location of a HARQ-ACK corresponding to adownlink subframe in the instantly scheduled downlink subframe subset.

Optionally, the sending module 1203 is further configured to: before thereceiving module 1201 receives the uplink control information sent bythe terminal, send, for a downlink subframe F(i, j) included in each ofthe at least one subset of preconfigured downlink subframes, firstindication information corresponding to the downlink subframe F(i, j) tothe terminal, where the first indication information is used to indicatea sequence number, according to a setting sequence, of the downlinksubframe F(i, j) in scheduled downlink subframes in the subset ofpreconfigured downlink subframes including the downlink subframe F(i,j); and instruct the terminal to generate the at least one sub-codebookin the following manner:

generating, for one of the at least one subset of preconfigured downlinksubframes according to the sequence number indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, the sending module 1203 is further configured to: before theprocessing module 1201 receives the uplink control information sent bythe terminal, receive second indication information to the terminal foreach of the at least one subset of preconfigured downlink subframes. Forcontent that the second indication information is used to indicate,refer to descriptions in the foregoing embodiments.

Optionally, the second indication information is used to indicate a bitquantity of a sub-codebook corresponding to the subset of preconfigureddownlink subframes including the downlink subframe F(i, j), and the bitquantity may also be referred to as a codebook size. The codebook sizeis less than a bit quantity of a HARQ-ACK corresponding to the subset ofpreconfigured downlink subframes but is greater than or equal to aquantity of downlink subframes in the instantly scheduled downlinksubframe subset or a quantity of transport blocks. When the codebooksize is greater than the quantity of downlink subframes in the instantlyscheduled downlink subframe subset or the quantity of transport blocks,both UE and a base station determine that at least one NACK is filled inat the end of the codebook, and a specific quantity of filled-in NACKsis the codebook size minus a quantity of downlink subframes that are inthe instantly scheduled downlink subframe subset and in which downlinkdata is actually scheduled or the quantity of transport blocks. Forspecific descriptions of this embodiment, refer to Embodiment 3. Detailsare not described herein again.

Alternatively, the second indication information may be used to instructthe terminal to:

generate, for one of the at least one subset of preconfigured downlinksubframes according to the second indication information and thesequence number that is indicated by the first indication informationand according to the receiving status of the downlink data received inthe downlink subframe F(i, j) and the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe F(i, j), a sub-codebookcorresponding to the one subset of preconfigured downlink subframes.

Optionally, the sending module 1203 is further configured to: before thereceiving module 1201 receives the uplink control information sent bythe terminal, send, for a downlink subframe F(i, j) included in each ofthe at least one subset of preconfigured downlink subframes, secondindication information corresponding to the downlink subframe F(i, j) tothe terminal.

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), A_(X−2), A₁, and A₀, valuesof the second indication information corresponding to other downlinksubframes are respectively A₀, the other downlink subframes are downlinksubframes, other than the last one, last but one, . . . , last but X−2,and last but X−1 of the sorted scheduled downlink subframes, in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to scheduled downlink subframes, sortedaccording to a reversed sequence of the setting sequence, in the subsetof preconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to the last one, last but one, . . . , lastbut X−2, and last but X−1 of scheduled downlink subframes that aresorted according to the setting sequence and whose subframe numbers arej are respectively A_(X−1), A_(X−2), A₁, and A₀, values of the secondindication information corresponding to other downlink subframes whosesequence numbers are j are respectively A₀, the other downlink subframeswhose sequence numbers are j are downlink subframes, other than the lastone, last but one, . . . , last but X−2, and last but X−1 of the sortedscheduled downlink subframes whose subframe numbers are j, in the subsetof preconfigured downlink subframes including the downlink subframe F(i,j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, values of the second indication information correspondingto scheduled downlink subframes that are sorted according to a reversedsequence of the setting sequence in the subset of preconfigured downlinksubframes and whose subframe numbers are j are respectively cyclicvalues of {A_(X−1), A_(X−2), A₁, A₀}.

X is a positive integer greater than 1.

The second indication information is used to instruct the terminal togenerate, for one of the at least one subset of preconfigured downlinksubframes according to the second indication information and thesequence number that is indicated by the first indication informationand according to the receiving status of the downlink data received inthe downlink subframe F(i, j) and the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe F(i, j), a sub-codebookcorresponding to the one subset of preconfigured downlink subframes.

Optionally, the setting sequence includes:

a sequence between a carrier and a subframe, a carrier sequence, and asubframe sequence.

The sequence between a carrier and a subframe includes: carriers beforesubframes, or subframes before carriers.

The carrier sequence includes: ascending order of carrier indexes, ordescending order of carrier indexes.

The subframe sequence includes: ascending order of subframe moments, ordescending order of subframe moments.

Optionally, the at least one sub-codebook is cascaded in the HARQ-ACKcodebook.

For an optional implementation solution of division of the set M ofpreconfigured downlink subframes, refer to related descriptions inEmbodiment 1.

For how the processing module 1202 generates the HARQ-ACK codebook byperforming channel decoding on the received uplink control information,obtains each sub-codebook, and determines the downlink data receivingstatus of the terminal according to the HARQ-ACK codebook, refer toprocessing performed by the access network device 201 in Embodiment 1 toEmbodiment 3.

For how the sending module 1203 sends the first indication informationand the second indication information, refer to processing performed bythe access network device 201 in Embodiment 1 to Embodiment 3.

For another optional implementation of the access network deviceprovided in Embodiment 5, refer to the foregoing access network device201. A repeated part is not described herein.

Specifically, the processing module 1202 is configured to perform aprocessing operation performed by the access network device 201, thereceiving module 1201 may be configured to perform a receiving operationperformed by the access network device 201, and the sending module 1203may be configured to perform a sending operation performed by the accessnetwork device 201.

FIG. 13 shows an optional implementation of the access network device.The processing module 1202 may be implemented by a processor 1302 inFIG. 13, the receiving module 1201 may be implemented by a receiver 1301in FIG. 13, and the sending module 1203 may be implemented by atransmitter 1303 in FIG. 13. A bus architecture may include any quantityof interconnected buses and bridges, and specifically link variouscircuits of one or more processors represented by the processor 1302 andone or more memories represented by a memory 1304. The bus architecturemay further link various other circuits such as a peripheral device, avoltage regulator, and a power management circuit, which is well knownin the art, and therefore no further description is provided in thisspecification. A bus interface provides an interface. The receiver 1301and the transmitter 1303 may be implemented by a transceiver thatprovides units for communicating with various other apparatuses on atransmission medium.

FIG. 14 shows another optional implementation of the access networkdevice. The processing module 1202 may be implemented by a processor1402 in FIG. 14, the receiving module 1201 may be implemented by areceiver 1401 in FIG. 14, and the sending module 1203 may be implementedby a transmitter 1403 in FIG. 14.

Embodiment 6

FIG. 15 is a flowchart of an uplink control information sending methodaccording to Embodiment 6 of the present disclosure. As shown in FIG.15, the method includes the following steps.

S1501. A terminal receives downlink scheduling information of a downlinksubframe F(i, j), where the downlink subframe F(i, j) is a subframe in aset M of preconfigured downlink subframes corresponding to an uplinksubframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a hybrid automatic repeatrequest-acknowledgement HARQ-ACK that needs to be fed back for eachdownlink subframe in one subset of preconfigured downlink subframes is apredetermined value, and bit quantities of HARQ-ACKs that need to be fedback for any downlink subframes in different subsets of preconfigureddownlink subframes are different.

S1502. The terminal receives, in the downlink subframe F(i, j), downlinkdata scheduled by the downlink scheduling information.

S1503. The terminal generates a HARQ-ACK codebook according to areceiving status of the downlink data received in the downlink subframeF(i, j) and a bit quantity of a HARQ-ACK that needs to be fed back forthe downlink subframe F(i, j), where the HARQ-ACK codebook includes atleast one sub-codebook, the at least one sub-codebook is in one-to-onecorrespondence with at least one subset of preconfigured downlinksubframes, the at least one subset of preconfigured downlink subframesis at least one of N subsets of preconfigured downlink subframes, andthe at least one subset of preconfigured downlink subframes is a subsetincluding the downlink subframe in which the terminal receives thedownlink data scheduled by the downlink scheduling information.

S1504. The terminal generates uplink control information by encoding theHARQ-ACK codebook.

S1505. The terminal sends the uplink control information in the uplinksubframe.

Optionally, a HARQ-ACK included in the sub-codebook is a HARQ-ACK for ascheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, but does not include aHARQ-ACK for an unscheduled downlink subframe in the subset ofpreconfigured downlink subframes corresponding to the sub-codebook.

Optionally, a HARQ-ACK included in the sub-codebook includes a HARQ-ACKfor a scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook; or a HARQ-ACK included inthe sub-codebook includes at least one filled-in bit and a HARQ-ACK fora scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, and the filled-in bit maybe a preset value such as a NACK. It should be noted that regardless ofwhether the filled-in NACK is included, a bit quantity of thesub-codebook needs to be less than a bit quantity of a HARQ-ACKcorresponding to a subset of preconfigured downlink subframes to whichan instantly scheduled downlink subframe subset belongs. The filled-inbit may be located after a bit location of a HARQ-ACK corresponding to adownlink subframe in the instantly scheduled downlink subframe subset.

Optionally, before the generating a HARQ-ACK codebook, the methodfurther includes:

receiving first indication information corresponding to a downlinksubframe F(i, j) included in each of the at least one subset ofpreconfigured downlink subframes, where the first indication informationis used to indicate a sequence number, according to a setting sequence,of the downlink subframe F(i, j) in scheduled downlink subframes in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j).

The at least one sub-codebook is generated in the following manner:

generating, by the terminal for one of the at least one subset ofpreconfigured downlink subframes according to the sequence numberindicated by the first indication information and according to thereceiving status of the downlink data received in the downlink subframeF(i, j) and the bit quantity of the HARQ-ACK that needs to be fed backfor the downlink subframe F(i, j), a sub-codebook corresponding to theone subset of preconfigured downlink subframes.

Optionally, before the generating a HARQ-ACK codebook, the methodfurther includes:

receiving second indication information corresponding to each of the atleast one subset of preconfigured downlink subframes. For contentindicated by the second indication information, refer to descriptions inthe foregoing embodiments.

Optionally, the second indication information is used to indicate a bitquantity of a sub-codebook corresponding to the subset of preconfigureddownlink subframes including the downlink subframe F(i, j), and the bitquantity may also be referred to as a codebook size. The codebook sizeis less than a bit quantity of a HARQ-ACK corresponding to the subset ofpreconfigured downlink subframes but is greater than or equal to aquantity of downlink subframes in the instantly scheduled downlinksubframe subset or a quantity of transport blocks. When the codebooksize is greater than the quantity of downlink subframes in the instantlyscheduled downlink subframe subset or the quantity of transport blocks,both UE and a base station determine that at least one NACK is filled inat the end of the codebook, and a specific quantity of filled-in NACKsis the codebook size minus a quantity of downlink subframes that are inthe instantly scheduled downlink subframe subset and in which downlinkdata is actually scheduled or the quantity of transport blocks. Forspecific descriptions of this embodiment, refer to Embodiment 3. Detailsare not described herein again.

The generating, by the terminal according to the sequence numberindicated by the first indication information and according to thereceiving status of the downlink data received in the downlink subframeF(i, j) and the bit quantity of the HARQ-ACK that needs to be fed backfor the downlink subframe F(i, j), a sub-codebook corresponding to theany subset of preconfigured downlink subframes includes:

generating, by the terminal for one of the at least one subset ofpreconfigured downlink subframes according to the second indicationinformation and the sequence number that is indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, before the generating a HARQ-ACK codebook, the methodfurther includes:

receiving second indication information corresponding to a downlinksubframe F(i, j) included in each of the at least one subset ofpreconfigured downlink subframes.

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), A_(X−2), A₁, and A₀, valuesof the second indication information corresponding to other downlinksubframes are respectively A₀, the other downlink subframes are downlinksubframes, other than the last one, last but one, . . . , last but X−2,and last but X−1 of the sorted scheduled downlink subframes, in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to scheduled downlink subframes, sortedaccording to a reversed sequence of the setting sequence, in the subsetof preconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to the last one, last but one, . . . , lastbut X−2, and last but X−1 of scheduled downlink subframes that aresorted according to the setting sequence and whose subframe numbers arej are respectively A_(X−1), A_(X−2), A₁, and A₀, values of the secondindication information corresponding to other downlink subframes whosesequence numbers are j are respectively A₀, the other downlink subframeswhose sequence numbers are j are downlink subframes, other than the lastone, last but one, . . . , last but X−2, and last but X−1 of the sortedscheduled downlink subframes whose subframe numbers are j, in the subsetof preconfigured downlink subframes including the downlink subframe F(i,j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, values of the second indication information correspondingto scheduled downlink subframes that are sorted according to a reversedsequence of the setting sequence in the subset of preconfigured downlinksubframes and whose subframe numbers are j are respectively cyclicvalues of {A_(X−1), A_(X−2), A₁, A₀}.

X is a positive integer greater than 1.

The generating, by the terminal according to the sequence numberindicated by the first indication information and according to thereceiving status of the downlink data received in the downlink subframeF(i, j) and the bit quantity of the HARQ-ACK that needs to be fed backfor the downlink subframe F(i, j), a sub-codebook corresponding to theany subset of preconfigured downlink subframes includes:

generating, by the terminal for one of the at least one subset ofpreconfigured downlink subframes according to the second indicationinformation and the sequence number that is indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, for the setting sequence, refer to the foregoingdescriptions.

Optionally, the at least one sub-codebook is cascaded in the HARQ-ACKcodebook.

For an optional implementation solution of division of the set M ofpreconfigured downlink subframes, refer to related descriptions inEmbodiment 1.

For an optional implementation in which the terminal generatessub-codebooks, forms the HARQ-ACK codebook by using the generatedsub-codebooks, generates the uplink control information by performingchannel encoding, and sends the uplink control information, refer toprocessing performed by the terminal 202 in Embodiment 1 to Embodiment3.

For an optional implementation in which the terminal receives the firstindication information and the second indication information anddetermines, according to the first indication information and the secondindication information, a downlink subframe scheduled by an accessnetwork device, refer to processing performed by the terminal 202 inEmbodiment 1 to Embodiment 3.

For another optional implementation of the uplink control informationsending method provided in Embodiment 6, refer to the foregoing terminal202. A repeated part is not described herein.

Embodiment 7

FIG. 16 is a flowchart of an uplink control information receiving methodaccording to Embodiment 7 of the present disclosure. As shown in FIG.16, the method includes the following steps.

S1601. An access network device sends downlink scheduling information ofa downlink subframe F(i, j) to a terminal, and sends, to the terminal inthe downlink subframe F(i, j), downlink data scheduled by the downlinkscheduling information, where the downlink subframe F(i, j) is asubframe in a set M of preconfigured downlink subframes corresponding toan uplink subframe.

F(i, j) represents a downlink subframe j on a carrier i configured forthe terminal, iϵC, C is a set of all carriers configured for theterminal for downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe.

The set M of preconfigured downlink subframes is divided into N subsetsof preconfigured downlink subframes, N is an integer greater than orequal to 2, a bit quantity of a HARQ-ACK that needs to be fed back foreach downlink subframe in one subset of preconfigured downlink subframesis a predetermined value, and bit quantities of hybrid automatic repeatrequest-acknowledgements HARQ-ACKs that need to be fed back for anydownlink subframes in different subsets of preconfigured downlinksubframes are different.

S1602. Receive uplink control information that is sent by the terminalin the uplink subframe and that is used for feeding back a receivingstatus of the downlink data scheduled by the downlink schedulinginformation.

S1603. Obtain a HARQ-ACK codebook by decoding the received uplinkcontrol information, where the obtained HARQ-ACK codebook includes atleast one sub-codebook, the at least one sub-codebook is in one-to-onecorrespondence with at least one subset of preconfigured downlinksubframes, the at least one subset of preconfigured downlink subframesis at least one of the N subsets of preconfigured downlink subframes,and the at least one subset of preconfigured downlink subframes is asubset including downlink subframes in which the downlink data scheduledby the downlink scheduling information is sent.

Optionally, a HARQ-ACK included in the sub-codebook is a HARQ-ACK for ascheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, but does not include aHARQ-ACK for an unscheduled downlink subframe in the subset ofpreconfigured downlink subframes corresponding to the sub-codebook.

Optionally, a HARQ-ACK included in the sub-codebook includes a HARQ-ACKfor a scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook; or a HARQ-ACK included inthe sub-codebook includes at least one filled-in bit and a HARQ-ACK fora scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the sub-codebook, and the filled-in bit maybe a preset value such as a NACK. It should be noted that regardless ofwhether the filled-in NACK is included, a bit quantity of thesub-codebook needs to be less than a bit quantity of a HARQ-ACKcorresponding to a subset of preconfigured downlink subframes to whichan instantly scheduled downlink subframe subset belongs. The filled-inbit may be located after a bit location of a HARQ-ACK corresponding to adownlink subframe in the instantly scheduled downlink subframe subset.

Optionally, before the receiving uplink control information that is sentby the terminal, the method further includes:

sending, for a downlink subframe F(i, j) included in each of the atleast one subset of preconfigured downlink subframes, first indicationinformation corresponding to the downlink subframe F(i, j) to theterminal, where the first indication information is used to indicate asequence number, according to a setting sequence, of the downlinksubframe F(i, j) in scheduled downlink subframes in the subset ofpreconfigured downlink subframes including the downlink subframe F(i,j); and

instructing the terminal to generate the at least one sub-codebook inthe following manner:

generating, for one of the at least one subset of preconfigured downlinksubframes according to the sequence number indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, before the receiving uplink control information that is sentby the terminal, the method further includes:

sending second indication information to the terminal for each of the atleast one subset of preconfigured downlink subframes, where the secondindication information is used to indicate:

a total quantity of scheduled downlink subframes whose subframe numbersare j and that are in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j); or a total quantity of ascheduled downlink subframe whose subframe number is j and a downlinksubframe before the downlink subframe whose subframe number is j, wherethe scheduled downlink subframe whose subframe number is j and thedownlink subframe before the downlink subframe whose subframe number isj are in the subset of preconfigured downlink subframes including thedownlink subframe F(i, j); or a total quantity of scheduled downlinksubframes in the subset of preconfigured downlink subframes includingthe downlink subframe F(i, j); or a total quantity of transport blockstransmitted in a scheduled downlink subframe that is in the subset ofpreconfigured downlink subframes including the downlink subframe F(i, j)and whose subframe number is j; or a total quantity of transport blockstransmitted in a scheduled downlink subframe whose subframe number is jand a downlink subframe before the downlink subframe whose subframenumber is j, where the scheduled downlink subframe whose subframe numberis j and the downlink subframe before the downlink subframe whosesubframe number is j are in the subset of preconfigured downlinksubframes including the downlink subframe F(i, j); or a total quantityof transport blocks transmitted in a scheduled downlink subframe in thesubset of preconfigured downlink subframes including the downlinksubframe F(i, j).

Optionally, the second indication information is used to indicate a bitquantity of a sub-codebook corresponding to the subset of preconfigureddownlink subframes including the downlink subframe F(i, j), and the bitquantity may also be referred to as a codebook size. The codebook sizeis less than a bit quantity of a HARQ-ACK corresponding to the subset ofpreconfigured downlink subframes but is greater than or equal to aquantity of downlink subframes in the instantly scheduled downlinksubframe subset or a quantity of transport blocks. When the codebooksize is greater than the quantity of downlink subframes in the instantlyscheduled downlink subframe subset or the quantity of transport blocks,both UE and a base station determine that at least one NACK is filled inat the end of the codebook, and a specific quantity of filled-in NACKsis the codebook size minus a quantity of downlink subframes that are inthe instantly scheduled downlink subframe subset and in which downlinkdata is actually scheduled or the quantity of transport blocks. Forspecific descriptions of this embodiment, refer to Embodiment 3. Detailsare not described herein again.

The terminal is instructed to generate, for one of the at least onesubset of preconfigured downlink subframes according to the secondindication information and the sequence number that is indicated by thefirst indication information and according to the receiving status ofthe downlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, before the receiving uplink control information that is sentby the terminal, the method further includes:

sending, for a downlink subframe F(i, j) included in each of the atleast one subset of preconfigured downlink subframes, second indicationinformation corresponding to the downlink subframe F(i, j) to theterminal.

In the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), Ax-2, . . . , A₁, and A₀,values of the second indication information corresponding to otherdownlink subframes are respectively A₀, the other downlink subframes aredownlink subframes, other than the last one, last but one, . . . , lastbut X−2, and last but X−1 of the sorted scheduled downlink subframes, inthe subset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), Ax-2, . . . , A₁, and A₀ are differentvalues.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to scheduled downlink subframes, sortedaccording to a reversed sequence of the setting sequence, in the subsetof preconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}.

Alternatively, in the subset of preconfigured downlink subframesincluding the downlink subframe F(i, j), values of the second indicationinformation corresponding to the last one, last but one, . . . , lastbut X−2, and last but X−1 of scheduled downlink subframes that aresorted according to the setting sequence and whose subframe numbers arej are respectively A_(X−1), Ax-2, . . . , A₁, and A₀, values of thesecond indication information corresponding to other downlink subframeswhose sequence numbers are j are respectively A₀, the other downlinksubframes whose sequence numbers are j are downlink subframes, otherthan the last one, last but one, . . . , last but X−2, and last but X−1of the sorted scheduled downlink subframes whose subframe numbers are j,in the subset of preconfigured downlink subframes including the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values.

Alternatively, values of the second indication information correspondingto scheduled downlink subframes that are sorted according to a reversedsequence of the setting sequence in the subset of preconfigured downlinksubframes and whose subframe numbers are j are respectively cyclicvalues of {A_(X−1), A_(X−2), A₁, A₀}.

X is a positive integer greater than 1.

The terminal is instructed to generate, for one of the at least onesubset of preconfigured downlink subframes according to the secondindication information and the sequence number that is indicated by thefirst indication information and according to the receiving status ofthe downlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.

Optionally, for the setting sequence, refer to the foregoingdescriptions.

Optionally, the at least one sub-codebook is cascaded in the HARQ-ACKcodebook.

For an optional implementation solution of division of the set M ofpreconfigured downlink subframes, refer to related descriptions inEmbodiment 1.

For how the access network device generates the HARQ-ACK codebook byperforming channel decoding on the received uplink control information,obtains each sub-codebook, and determines the downlink data receivingstatus of the terminal according to the HARQ-ACK codebook, refer toprocessing performed by the access network device 201 in Embodiment 1 toEmbodiment 3.

For how the access network device sends the first indication informationand the second indication information, refer to processing performed bythe access network device 201 in Embodiment 1 to Embodiment 3.

For another optional implementation of the uplink control informationreceiving method provided in Embodiment 7, refer to the foregoing accessnetwork device 201. A repeated part is not described herein.

In conclusion, in this embodiment of the present disclosure, the set Mof preconfigured downlink subframes is divided into the foregoing Nsubset of preconfigured downlink subframes, the bit quantity of theHARQ-ACK that needs to be fed back for each downlink subframe in onesubset of preconfigured downlink subframes is a predetermined value, andthe bit quantities of the HARQ-ACKs that need to be fed back for anydownlink subframes in different subsets of preconfigured downlinksubframes are different. In this way, when generating an ACK/NACKcodebook, the terminal feeds back a HARQ-ACK according to the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe in the subset of preconfigured downlink subframes. Therefore,when the access network device parses, after receiving the uplinkcontrol information generated according to the HARQ-ACK codebook, theACK/NACK codebook according to the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe in the subset ofpreconfigured downlink subframes, a HARQ-ACK feedback solution isprovided, so that a case in which bit quantities of HARQ-ACKs that needto be fed back for downlink subframes on different to-be-aggregatedcarriers are different can be supported.

Persons skilled in the art should understand that the embodiments of thepresent disclosure may be provided as a method, a system, or a computerprogram product. Therefore, the present disclosure may use a form ofhardware-only embodiments, software-only embodiments, or embodimentswith a combination of software and hardware. Moreover, the presentdisclosure may be in a form of a computer program product that isimplemented on one or more computer-usable storage media (including butnot limited to a disk memory, a CD-ROM, an optical memory, and the like)that include computer-usable program code.

The present disclosure is described with reference to the flowchartsand/or block diagrams of the method, the device (system), and thecomputer program product according to the embodiments of the presentdisclosure. It should be understood that computer program instructionsmay be used to implement each process and/or each block in theflowcharts and/or the block diagrams and a combination of a processand/or a block in the flowcharts and/or the block diagrams. Thesecomputer program instructions may be provided for a general-purposecomputer, a dedicated computer, an embedded processor, or a processor ofany other programmable data processing device to generate a machine, sothat the instructions executed by a computer or a processor of any otherprogrammable data processing device generate an apparatus forimplementing a specific function in one or more processes in theflowcharts and/or in one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readablememory that can instruct the computer or any other programmable dataprocessing device to work in a specific manner, so that the instructionsstored in the computer readable memory generate an artifact thatincludes an instruction apparatus. The instruction apparatus implementsa specific function in one or more processes in the flowcharts and/or inone or more blocks in the block diagrams.

These computer program instructions may be loaded onto a computer oranother programmable data processing device, so that a series ofoperations and steps are performed on the computer or the anotherprogrammable device, thereby generating computer-implemented processing.Therefore, the instructions executed on the computer or the anotherprogrammable device provide steps for implementing a specific functionin one or more processes in the flowcharts and/or in one or more blocksin the block diagrams.

Although some preferred embodiments of the present disclosure have beendescribed, persons skilled in the art can make changes and modificationsto these embodiments once they learn the basic inventive concept.Therefore, the following claims are intended to be construed as to coverthe preferred embodiments and all changes and modifications fallingwithin the scope of the present disclosure.

Obviously, persons skilled in the art can make various modifications andvariations to the embodiments of the present disclosure withoutdeparting from the spirit and scope of the embodiments of the presentdisclosure. In this way, the present disclosure is intended to coverthese modifications and variations provided that they fall within thescope of protection defined by the following claims and their equivalenttechnologies.

1. An apparatus, comprising: a storage medium including executableinstructions; and a processor; wherein the executable instructions, whenexecuted by the processor, cause the apparatus to: receive downlinkscheduling information of a downlink subframe F(i, j), wherein thedownlink subframe F(i, j) is a subframe in a set M of preconfigureddownlink subframes corresponding to an uplink subframe, wherein F(i, j)represents a downlink subframe j on a carrier i configured for theterminal, jϵC, C is a set of all carriers configured for the terminalfor downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe, the set M ofpreconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframes, N is an integer greater than or equalto 2, a bit quantity of a hybrid automatic repeatrequest-acknowledgement (HARQ-ACK) that needs to be fed back for eachdownlink subframe in one subset of preconfigured downlink subframes is apredetermined value, and bit quantities of HARQ-ACKs that need to be fedback for any downlink subframes in different subsets of preconfigureddownlink subframes are different; and receive, in the downlink subframeF(i, j), downlink data scheduled by the downlink scheduling information;generate a HARQ-ACK codebook according to a receiving status of thedownlink data in the downlink subframe F(i, j) and a bit quantity of aHARQ-ACK that needs to be fed back for the downlink subframe F(i, j),wherein the HARQ-ACK codebook comprises at least one sub-codebook, theat least one sub-codebook is in one-to-one correspondence with at leastone subset of preconfigured downlink subframes, the at least one subsetof preconfigured downlink subframes is at least one of the N subsets ofpreconfigured downlink subframes, and the at least one subset ofpreconfigured downlink subframes is a subset comprising the downlinksubframe in which the terminal receives the downlink data scheduled bythe downlink scheduling information; and generate uplink controlinformation by encoding the HARQ-ACK codebook; and send the uplinkcontrol information in the uplink subframe.
 2. The apparatus accordingto claim 1, wherein the at least one sub-codebook comprises a HARQ-ACKfor a scheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the at least one sub-codebook, but does notcomprise a HARQ-ACK for an unscheduled downlink subframe in the subsetof preconfigured downlink subframes corresponding to the at least onesub-codebook.
 3. The apparatus according to claim 2, wherein theexecutable instructions, when executed by the processor, further causethe apparatus to: before the HARQ-ACK codebook is generated, receivefirst indication information corresponding to a downlink subframe F(i,j) comprised in each of the at least one subset of preconfigureddownlink subframes, wherein the first indication information is used toindicate a sequence number, according to a setting sequence, of thedownlink subframe F(i, j) in scheduled downlink subframes in the subsetof preconfigured downlink subframes comprising the downlink subframeF(i, j), and generate the at least one sub-codebook by: generating, forone of the at least one subset of preconfigured downlink subframesaccording to the sequence number indicated by the first indicationinformation and according to the receiving status of the downlink datareceived in the downlink subframe F(i, j) and the bit quantity of theHARQ-ACK that needs to be fed back for the downlink subframe F(i, j), asub-codebook corresponding to the one subset of preconfigured downlinksubframes.
 4. The apparatus according to claim 3, wherein the executableinstructions, when executed by the processor, further cause theapparatus to: before the HARQ-ACK codebook is generated, receive secondindication information corresponding to each of the at least one subsetof preconfigured downlink subframes, wherein the second indicationinformation is used to indicate: a total quantity of scheduled downlinksubframes that are in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe numbers arej; or a total quantity of a scheduled downlink subframe whose subframenumber is j and a downlink subframe before the downlink subframe whosesubframe number is j, wherein the scheduled downlink subframe whosesubframe number is j and the downlink subframe before the downlinksubframe whose subframe number is j are in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of scheduled downlink subframes in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of transport blocks transmitted in a scheduled downlinksubframe that is in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe number is j;or a total quantity of transport blocks transmitted in a scheduleddownlink subframe whose subframe number is j and a downlink subframebefore the downlink subframe whose subframe number is j, wherein thescheduled downlink subframe whose subframe number is j and the downlinksubframe before the downlink subframe whose subframe number is j are inthe subset of preconfigured downlink subframes comprising the downlinksubframe F(i, j); or a total quantity of transport blocks transmitted ina scheduled downlink subframe in the subset of preconfigured downlinksubframes comprising the downlink subframe F(i, j); and generate, forone of the at least one subset of preconfigured downlink subframesaccording to the second indication information and the sequence numberthat is indicated by the first indication information and according tothe receiving status of the downlink data received in the downlinksubframe F(i, j) and the bit quantity of the HARQ-ACK that needs to befed back for the downlink subframe F(i, j), a sub-codebook correspondingto the one subset of preconfigured downlink subframes.
 5. The apparatusaccording to claim 3, wherein the executable instructions, when executedby the processor, further cause the apparatus to: before the processingmodule generates the HARQ-ACK codebook, receive second indicationinformation corresponding to a downlink subframe F(i, j) comprised ineach of the at least one subset of preconfigured downlink subframes;wherein in the subset of preconfigured downlink subframes comprising thedownlink subframe F(i, j), values of the second indication informationcorresponding to the last one, last but one, . . . , last but X−2, andlast but X−1 of scheduled downlink subframes sorted according to thesetting sequence are respectively A_(X−1), A_(X−2), A₁, and A₀, valuesof the second indication information corresponding to other downlinksubframes are respectively A₀, the other downlink subframes are downlinksubframes, other than the last one, last but one, . . . , last but X−2,and last but X−1 of the sorted scheduled downlink subframes, in thesubset of preconfigured downlink subframes comprising the downlinksubframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ are different values;or in the subset of preconfigured downlink subframes comprising thedownlink subframe F(i, j), values of the second indication informationcorresponding to scheduled downlink subframes, sorted according to areversed sequence of the setting sequence, in the subset ofpreconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}; or in the subset of preconfigured downlinksubframes comprising the downlink subframe F(i, j), values of the secondindication information corresponding to the last one, last but one, . .. , last but X−2, and last but X−1 of scheduled downlink subframes thatare sorted according to the setting sequence and whose subframe numbersare j are respectively A_(X−1), A_(X−2), . . . , A₁, and A₀, values ofthe second indication information corresponding to other downlinksubframes whose sequence numbers are j are respectively A₀, the otherdownlink subframes whose sequence numbers are j are downlink subframes,other than the last one, last but one, . . . , last but X−2, and lastbut X−1 of the sorted scheduled downlink subframes whose subframenumbers are j, in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j), and A_(X−1), A_(X−2), A₁, andA₀ are different values; or values of the second indication informationcorresponding to scheduled downlink subframes that are sorted accordingto a reversed sequence of the setting sequence in the subset ofpreconfigured downlink subframes and whose subframe numbers are j arerespectively cyclic values of {A_(X−1), A_(X−2), A₁, A₀}; wherein X is apositive integer greater than 1; and generate, for one of the at leastone subset of preconfigured downlink subframes according to the secondindication information and the sequence number that is indicated by thefirst indication information and according to the receiving status ofthe downlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), a sub-codebook corresponding to the one subset ofpreconfigured downlink subframes.
 6. The apparatus according to claim 3,wherein the setting sequence comprises: a sequence between a carrier anda subframe, a carrier sequence, and a subframe sequence; wherein thesequence between a carrier and a subframe comprises: carriers beforesubframes, or subframes before carriers; the carrier sequence comprises:ascending order of carrier indexes, or descending order of carrierindexes; and the subframe sequence comprises: ascending order ofsubframe moments, or descending order of subframe moments.
 7. Theapparatus according to claim 1, wherein the at least one sub-codebook iscascaded in the HARQ-ACK codebook.
 8. A method, comprising: receivingdownlink scheduling information of a downlink subframe F(i, j), whereinthe downlink subframe F(i, j) is a subframe in a set M of preconfigureddownlink subframes corresponding to an uplink subframe, wherein F(i, j)represents a downlink subframe j on a carrier i configured for aterminal, iϵC, C is a set of all carriers configured for the terminalfor downlink data transmission, jϵK, and K is a set of downlinksubframes corresponding to the uplink subframe, the set M ofpreconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframe, N is an integer greater than or equalto 2, a bit quantity of a hybrid automatic repeatrequest-acknowledgement (HARQ-ACK) that needs to be fed back for eachdownlink subframe in one subset of preconfigured downlink subframes is apredetermined value, and bit quantities of HARQ-ACKs that need to be fedback for any downlink subframes in different subsets of preconfigureddownlink subframes are different; receiving, in the downlink subframeF(i, j), downlink data scheduled by the downlink scheduling information;generating a HARQ-ACK codebook according to a receiving status of thedownlink data received in the downlink subframe F(i, j) and a bitquantity of a HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), wherein the HARQ-ACK codebook comprises at least onesub-codebook, the at least one sub-codebook is in one-to-onecorrespondence with at least one subset of preconfigured downlinksubframes, the at least one subset of preconfigured downlink subframesis at least one of the N subsets of preconfigured downlink subframes,and the at least one subset of preconfigured downlink subframes is asubset comprising the downlink subframe in which the terminal receivesthe downlink data scheduled by the downlink scheduling information;generating uplink control information by encoding the HARQ-ACK codebook;and sending the uplink control information in the uplink subframe. 9.The method according to claim 8, wherein the at least one sub-codebookcomprises a HARQ-ACK for a scheduled downlink subframe in a subset ofpreconfigured downlink subframes corresponding to the at least onesub-codebook, but does not comprise a HARQ-ACK for an unscheduleddownlink subframe in the subset of preconfigured downlink subframescorresponding to the at least one sub-codebook.
 10. The method accordingto claim 9, wherein: before the generating a HARQ-ACK codebook, themethod further comprises: receiving first indication informationcorresponding to a downlink subframe F(i, j) comprised in each of the atleast one subset of preconfigured downlink subframes, wherein the firstindication information is used to indicate a sequence number, accordingto a setting sequence, of the downlink subframe F(i, j) in scheduleddownlink subframes in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j); and the at least onesub-codebook is generated by: generating, for one of the at least onesubset of preconfigured downlink subframes according to the sequencenumber indicated by the first indication information and according tothe receiving status of the downlink data received in the downlinksubframe F(i, j) and the bit quantity of the HARQ-ACK that needs to befed back for the downlink subframe F(i, j), a sub-codebook correspondingto the one subset of preconfigured downlink subframes.
 11. The methodaccording to claim 10, wherein: before the generating a HARQ-ACKcodebook, the method further comprises: receiving second indicationinformation corresponding to each of the at least one subset ofpreconfigured downlink subframes, wherein the second indicationinformation is used to indicate: a total quantity of scheduled downlinksubframes that are in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe numbers arej; or a total quantity of a scheduled downlink subframe whose subframenumber is j and a downlink subframe before the downlink subframe whosesubframe number is j, wherein the scheduled downlink subframe whosesubframe number is j and the downlink subframe before the downlinksubframe whose subframe number is j are in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of scheduled downlink subframes in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of transport blocks transmitted in a scheduled downlinksubframe that is in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe number is j;or a total quantity of transport blocks transmitted in a scheduleddownlink subframe whose subframe number is j and a downlink subframebefore the downlink subframe whose subframe number is j, wherein thescheduled downlink subframe whose subframe number is j and the downlinksubframe before the downlink subframe whose subframe number is j are inthe subset of preconfigured downlink subframes comprising the downlinksubframe F(i, j); or a total quantity of transport blocks transmitted ina scheduled downlink subframe in the subset of preconfigured downlinksubframes comprising the downlink subframe F(i, j); and the generating,according to the sequence number indicated by the first indicationinformation and according to the receiving status of the downlink datareceived in the downlink subframe F(i, j) and the bit quantity of theHARQ-ACK that needs to be fed back for the downlink subframe F(i, j), atleast one sub-codebook corresponding to the one subset of preconfigureddownlink subframes comprises: generating, for one of the at least onesubset of preconfigured downlink subframes according to the secondindication information and the sequence number that is indicated by thefirst indication information and according to the receiving status ofthe downlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), the at least one sub-codebook corresponding to the onesubset of preconfigured downlink subframes.
 12. The method according toclaim 10, wherein: before the generating a HARQ-ACK codebook, the methodfurther comprises: receiving second indication information correspondingto a downlink subframe F(i, j) comprised in each of the at least onesubset of preconfigured downlink subframes; wherein in the subset ofpreconfigured downlink subframes comprising the downlink subframe F(i,j), values of the second indication information corresponding to thelast one, last but one, . . . , last but X−2, and last but X−1 ofscheduled downlink subframes sorted according to the setting sequenceare respectively A_(X−1), A_(X−2), A₁, and A₀, values of the secondindication information corresponding to other downlink subframes arerespectively A₀, the other downlink subframes are downlink subframes,other than the last one, last but one, . . . , last but X−2, and lastbut X−1 of the sorted scheduled downlink subframes, in the subset ofpreconfigured downlink subframes comprising the downlink subframe F(i,j), and A_(X−1), A_(X−2), A₁, and A₀ are different values; or in thesubset of preconfigured downlink subframes comprising the downlinksubframe F(i, j), values of the second indication informationcorresponding to scheduled downlink subframes, sorted according to areversed sequence of the setting sequence, in the subset ofpreconfigured downlink subframes are respectively cyclic values of{A_(X−1), A_(X−2), A₁, A₀}; or in the subset of preconfigured downlinksubframes comprising the downlink subframe F(i, j), values of the secondindication information corresponding to the last one, last but one, . .. , last but X−2, and last but X−1 of scheduled downlink subframes thatare sorted according to the setting sequence and whose subframe numbersare j are respectively A_(X−1), Ax-2, . . . , A₁, and A₀, values of thesecond indication information corresponding to other downlink subframeswhose sequence numbers are j are respectively A₀, the other downlinksubframes whose sequence numbers are j are downlink subframes, otherthan the last one, last but one, . . . , last but X−2, and last but X−1of the sorted scheduled downlink subframes whose subframe numbers are j,in the subset of preconfigured downlink subframes comprising thedownlink subframe F(i, j), and A_(X−1), A_(X−2), A₁, and A₀ aredifferent values; or values of the second indication informationcorresponding to scheduled downlink subframes that are sorted accordingto a reversed sequence of the setting sequence in the subset ofpreconfigured downlink subframes and whose subframe numbers are j arerespectively cyclic values of {A_(X−1), A_(X−2), A₁, A₀}; wherein X is apositive integer greater than 1; and the generating, according to thesequence number indicated by the first indication information andaccording to the receiving status of the downlink data received in thedownlink subframe F(i, j) and the bit quantity of the HARQ-ACK thatneeds to be fed back for the downlink subframe F(i, j), at least onesub-codebook corresponding to the any subset of preconfigured downlinksubframes comprises: generating, for one of the at least one subset ofpreconfigured downlink subframes according to the second indicationinformation and the sequence number that is indicated by the firstindication information and according to the receiving status of thedownlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), the at least one sub-codebook corresponding to the onesubset of preconfigured downlink subframes.
 13. The method according toclaim 10, wherein the setting sequence comprises: a sequence between acarrier and a subframe, a carrier sequence, and a subframe sequence;wherein the sequence between a carrier and a subframe comprises:carriers before subframes, or subframes before carriers; the carriersequence comprises: ascending order of carrier indexes, or descendingorder of carrier indexes; and the subframe sequence comprises: ascendingorder of subframe moments, or descending order of subframe moments. 14.The method according to claim 8, wherein the at least one sub-codebookis cascaded in the HARQ-ACK codebook.
 15. A non-transitorycomputer-readable storage medium comprising instructions which, whenexecuted by a computer, cause the computer to carry out the steps of:receiving downlink scheduling information of a downlink subframe F(i,j), wherein the downlink subframe F(i, j) is a subframe in a set M ofpreconfigured downlink subframes corresponding to an uplink subframe,wherein F(i, j) represents a downlink subframe j on a carrier iconfigured for a terminal, iϵC, C is a set of all carriers configuredfor the terminal for downlink data transmission, jϵK, and K is a set ofdownlink subframes corresponding to the uplink subframe, the set M ofpreconfigured downlink subframes is divided into N subsets ofpreconfigured downlink subframe, N is an integer greater than or equalto 2, a bit quantity of a hybrid automatic repeatrequest-acknowledgement (HARQ-ACK) that needs to be fed back for eachdownlink subframe in one subset of preconfigured downlink subframes is apredetermined value, and bit quantities of HARQ-ACKs that need to be fedback for any downlink subframes in different subsets of preconfigureddownlink subframes are different; receiving, in the downlink subframeF(i, j), downlink data scheduled by the downlink scheduling information;generating a HARQ-ACK codebook according to a receiving status of thedownlink data received in the downlink subframe F(i, j) and a bitquantity of a HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), wherein the HARQ-ACK codebook comprises at least onesub-codebook, the at least one sub-codebook is in one-to-onecorrespondence with at least one subset of preconfigured downlinksubframes, the at least one subset of preconfigured downlink subframesis at least one of the N subsets of preconfigured downlink subframes,and the at least one subset of preconfigured downlink subframes is asubset comprising the downlink subframe in which the terminal receivesthe downlink data scheduled by the downlink scheduling information;generating uplink control information by encoding the HARQ-ACK codebook;and sending the uplink control information in the uplink subframe. 16.The non-transitory computer-readable storage medium according to claim15, wherein the at least one sub-codebook comprises a HARQ-ACK for ascheduled downlink subframe in a subset of preconfigured downlinksubframes corresponding to the at least one sub-codebook, but does notcomprise a HARQ-ACK for an unscheduled downlink subframe in the subsetof preconfigured downlink subframes corresponding to the at least onesub-codebook.
 17. The non-transitory computer-readable storage mediumaccording to claim 16, comprising instructions which, when executed by acomputer, further cause the computer to carry out the steps of:receiving first indication information corresponding to a downlinksubframe F(i, j) comprised in each of the at least one subset ofpreconfigured downlink subframes, wherein the first indicationinformation is used to indicate a sequence number, according to asetting sequence, of the downlink subframe F(i, j) in scheduled downlinksubframes in the subset of preconfigured downlink subframes comprisingthe downlink subframe F(i, j); and wherein the at least one sub-codebookis generated by: generating, for one of the at least one subset ofpreconfigured downlink subframes according to the sequence numberindicated by the first indication information and according to thereceiving status of the downlink data received in the downlink subframeF(i, j) and the bit quantity of the HARQ-ACK that needs to be fed backfor the downlink subframe F(i, j), a sub-codebook corresponding to theone subset of preconfigured downlink subframes.
 18. The non-transitorycomputer-readable storage medium according to claim 17, comprisinginstructions which, when executed by a computer, further cause thecomputer to carry out the steps of: before the generating a HARQ-ACKcodebook, the method further comprises: receiving second indicationinformation corresponding to each of the at least one subset ofpreconfigured downlink subframes, wherein the second indicationinformation is used to indicate: a total quantity of scheduled downlinksubframes that are in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe numbers arej; or a total quantity of a scheduled downlink subframe whose subframenumber is j and a downlink subframe before the downlink subframe whosesubframe number is j, wherein the scheduled downlink subframe whosesubframe number is j and the downlink subframe before the downlinksubframe whose subframe number is j are in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of scheduled downlink subframes in the subset of preconfigureddownlink subframes comprising the downlink subframe F(i, j); or a totalquantity of transport blocks transmitted in a scheduled downlinksubframe that is in the subset of preconfigured downlink subframescomprising the downlink subframe F(i, j) and whose subframe number is j;or a total quantity of transport blocks transmitted in a scheduleddownlink subframe whose subframe number is j and a downlink subframebefore the downlink subframe whose subframe number is j, wherein thescheduled downlink subframe whose subframe number is j and the downlinksubframe before the downlink subframe whose subframe number is j are inthe subset of preconfigured downlink subframes comprising the downlinksubframe F(i, j); or a total quantity of transport blocks transmitted ina scheduled downlink subframe in the subset of preconfigured downlinksubframes comprising the downlink subframe F(i, j); and the generating,according to the sequence number indicated by the first indicationinformation and according to the receiving status of the downlink datareceived in the downlink subframe F(i, j) and the bit quantity of theHARQ-ACK that needs to be fed back for the downlink subframe F(i, j), atleast one sub-codebook corresponding to the one subset of preconfigureddownlink subframes comprises: generating, for one of the at least onesubset of preconfigured downlink subframes according to the secondindication information and the sequence number that is indicated by thefirst indication information and according to the receiving status ofthe downlink data received in the downlink subframe F(i, j) and the bitquantity of the HARQ-ACK that needs to be fed back for the downlinksubframe F(i, j), the at least one sub-codebook corresponding to the onesubset of preconfigured downlink subframes.
 19. The non-transitorycomputer-readable storage medium according to claim 18, wherein asequence between a carrier and a subframe, a carrier sequence, and asubframe sequence; wherein the sequence between a carrier and a subframecomprises: carriers before subframes, or subframes before carriers; thecarrier sequence comprises: ascending order of carrier indexes, ordescending order of carrier indexes; and the subframe sequencecomprises: ascending order of subframe moments, or descending order ofsubframe moments.
 20. The non-transitory computer-readable storagemedium according to claim 15, wherein the at least one sub-codebook iscascaded in the HARQ-ACK codebook.